15More about Probability

15 More about Probability

Note: All the questions in this chapter are on non-foundation part.

Extra Examples

(P01C15L01Q001)
Example 15.1R
A bag contains 6 blue balls and 9 yellow balls. One ball is drawn at random from the bag. Find the
probability that
(a) the ball drawn is blue,
(b) the ball drawn is yellow.

(P01C15L01Q002)
Example 15.2R
A die is thrown. Find the probability of getting
(a) a number less than 4,
(b) a number less than 1,
(c) a number greater than 0.

(P01C15L01Q003)
Example 15.3R
Box A contains 1 black ball, 2 red balls and 1 green ball. Box B contains 1 black ball and 2 red balls. One
ball is drawn at random from each of the box. Find the probability that
(a) the two balls are of the same colour,
(b) one ball is black and the other one is red.

(P01C15L01Q004)
Example 15.4R
When tossing 3 fair coins, determine the probability of getting
(a) 3 tails,
(b) at least 1 head.

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Question Bank

(P01C15L01Q005)
Example 15.5R
There are 20 boxes of electronic devices. The number of defective devices in each box is counted and the
results are shown in the following table:
No. of defective devices 0 1 2 3
No. of boxes 8 5 4 3
If a box is selected randomly, find the probability that it contains
(a) no defective devices,
(b) more than one defective devices.

(P01C15L01Q006)
Example 15.6R
In a forum, a group of peple commented on the topic ‘one should put on a mask when having a flu’. The
result is summarized in the following table. (Each person could only choose one response.)
Response Frequency
Agree 148
Disagree 35
No comment 67
If a person is chosen at random from this group of people, find the probability that
(a) the person’s response is either ‘agree’ or ‘disagree’,
(b) the person is not against to put on a mask when having a flu.

(P01C15L01Q007)
Example 15.7R
Mary is choosing a new umbrella in a shop. The table below shows the probability of the colours she will
choose.
Colour of the umbrella Black Red Yellow Blue Green White
Probability 0.08 0.21 0.32 0.27 0.11 0.01
Find the probability that she chooses
(a) a black or white umbrella,
(b) a red or blue umbrella.

(P01C15L01Q008)
Example 15.8R
2
In a city, a survey shows that the probability of a person dies before 40 is . What is the probability of a
7

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 15More about Probability

person dies at or after 40?

(P01C15L01Q009)
Example 15.9R
Four coins are tossed. Find the probability of getting at least one tail.

(P01C15L01Q010)
Example 15.10R
Two dice are thrown. Find the probability that the sum of the two numbers are smaller than 11.

(P01C15L01Q011)
Example 15.11R
It is given that class A has 21 boys and 19 girls, while class B has 22 boys and 20 girls. If one representative
is chosen at random from each class, find the probability that the two representatives are boys.

(P01C15L01Q012)
Example 15.12R
Three cards are drawn at random from a well-shuffled deck of 52 cards one after the other with
replacement. Find the probability that
(a) all the three cards are red,
(b) at least one black card is drawn.

(P01C15L01Q013)
Example 15.13R
Box A contains 2 white balls, 4 black balls and 6 red balls. Box B contains 5 white balls, 6 black balls and 7
red balls. One ball is drawn from each box at random. Find the probability that both balls are
(a) red,
(b) black,
(c) of the same colour.

(P01C15L01Q014)
Example 15.14R
2 3 1
The probabilities that Alan passes the Chinese, English and Mathematics examination are , and
3 4 2
respectively. Find the probability that he passes exactly two of the three subjects in the examination.

(P01C15L01Q015)

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Question Bank

Example 15.15R
A family has two children and one of them is a boy. Find the probability that both of them are boys.

(P01C15L01Q016)
Example 15.16R
Two cards are drawn at random from a deck of 52 cards without replacement. If the first card drawn is the
king of spades, find the probability that the second card drawn is
(a) also a king,
(b) a face card.

(P01C15L01Q017)
Example 15.17R
A survey on ‘your favourite fast food shop’ is carried out in a school and the result is recorded below:
Fast food shop Boy Girl
Hamburger Queen 240 160
Fairwell 54 72
Café de Mary 102 96
Delimexico 87 242
(Each student can only choose one fast food shop.)
A student is chosen at random from the group.
(a) If the student’s favourite fast food shop is ‘Hamburger Queen’, find the probability that the student is
a boy.
(b) If the student is a girl, find the probability that her favourite fast food shop is ‘Delimexico’.
(c) If the student’s favourite fast food shop is ‘Fairwell’, find the probability that the student is a girl.

(P01C15L01Q018)
Example 15.18R
Two cards are selected randomly from a deck of 52 playing cards without replacement. Find the probability
that
(a) two red cards are drawn,
(b) the first one is an ace and the second one is a queen.

(P01C15L01Q019)
Example 15.19R
There are 8 red socks and 6 white socks in a drawer. Peter randomly takes out 2 socks from the drawer in
the dark without replacement.
(a) What is the probability that the socks taken out are both red?

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 15More about Probability

(b) What is the probability that the socks taken out are of the same colour?

(P01C15L01Q020)
Example 15.20R
In a city, 55% of the population is male. The percentages of left-handed males and females in the
population are 5% and 8% respectively. If a person is selected at random, find the probability that the
person is left-handed.

(P01C15L01Q021)
Example 15.12X
Three dice are thrown. Find the probability that
(a) all the three numbers are all odd,
(b) the product of the three numbers is even.

(P01C15L01Q022)
Example 15.14X
Team A and team B enter the final of a basketball competition. The team which wins 3 games first would be
the champion of the competition. Statistics shows that team A has a probability of 0.55 to win a game.
(a) Find the probability that team A wins the competitions by playing
(i) 3 matches,
(ii) 4 matches
(iii) 5 matches.
(b) Hence find the probability that team A wins the competition.
(Give your answers correct to 3 significant figures.)

(P01C15L01Q023)
Example 15.20X
Box A contains 40 batteries, 10 of which are defective. Box B contains 30 batteries, 5 of which are
defective. The batteries in the two boxes are mixed and one battery is selected at random.
(a) If the selected battery is defective, what is the probability that it comes from box A?
(b) If the selected battery is non-defective, what is the probability that it comes from box A?

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Question Bank

Pre-requisite Questions

(P01C15L02Q001)
1. If a die is thrown, find the probability the number is
(a) equal to 2,
(b) less than 8,
(c) greater than 6.

(P01C15L02Q002)
2. A card is drawn at random from a well-shuffled deck of 52 cards. Find the probability that it is
(a) an ace of spades,
(b) a club,
(c) a red card.

(P01C15L02Q003)
3. A letter is chosen randomly from the word ‘MILLENNIUM’. Find the probability of getting
(a) an ‘L’,
(b) a vowel,
(c) a consonant.

(P01C15L02Q004)
4. A loaded die is thrown 1000 times with the results recorded below:
Number 1 2 3 4 5 6
Frequency 137 243 242 87 103 188
Find the experimental probability of getting
(a) a ‘3’,
(b) an even number,
(c) a prime number.

(P01C15L02Q005)
5. A sock is drawn randomly from a drawer containing two pairs of white socks, three pairs of black
socks and one pair of blue socks. Find the probability of drawing
(a) a white sock,
(b) a black sock,
(c) a red sock.

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 15More about Probability

(P01C15L02Q006)
6. One biased coin and one fair coin are thrown 100 times. The results are recorded in the following
table.
Result No head 1 head only
No. of occurrence 45 35
Find the experimental probability of getting
(a) 2 heads,
(b) 2 tails.

(P01C15L02Q007)
7. A die is thrown 1000 times, in which ‘2’ shows up 105 times. Find
(a) the theoretical probability of getting a ‘2’,
(b) the experimental probability of getting a ‘2’.

(P01C15L02Q008)
8. Two fair coins are thrown, find the probability of getting
(a) two heads,
(b) two tails,
(c) exactly one head.

(P01C15L02Q009)
9. A die is thrown, find the probability of getting
(a) an even number,
(b) an odd number,
(c) a prime number.

(P01C15L02Q010)
10. Mrs. Chan has two sons and one daughter. Find the probability that the daughter is the eldest.

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Question Bank

Level 1 Questions

(P01C15L03Q001)
1. Three fair coins are thrown. Find the probability of getting
(a) 3 tails,
(b) exactly 2 heads.

(P01C15L03Q002)
2. The pie chart shows the different means of transport the F.1 students
of a school take when they go to school. If a student is chosen at
random from the school, find the probability that he goes to school
(a) by bus,
(b) by taxi,
(c) by bus or taxi,
(d) neither by mini-bus nor MTR.

(P01C15L03Q003)
3. The following table shows the distribution of weights of 100 men in a body check-up activity.
Weight / kg 30 – 39 40 – 49 50 – 59 60 – 69 70 – 79 80 – 89
Frequency 18 2x + 1 20 12 13 x
(a) Find x.
(b) For a man who joined the body check-up activity, find the probability that his weight is
(i) between 59.5 kg and 79.5 kg,
(ii) between 39.5 kg and 49.5 kg.

(P01C15L03Q004)
4. Two dice are thrown. Find the probability that the sum of the two numbers is
(a) even,
(b) equal to 7,
(c) a prime number.

(P01C15L03Q005)
5. An ant travels around the perimeter of a pentagon and stops at a random location.
What is the probability that it lands on the longest side?

(P01C15L03Q006)

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 15More about Probability

6. If 97XX is a 4-digit number where the last two digits are equal, what is the probability that it is
divisible by 3?
(P01C15L03Q007)
7. Two cards are drawn at random from a deck of 52 well-shuffled cards. If the first card drawn is a
black number card, what is the probability that the second card drawn is the ace of clubs?

(P01C15L03Q008)
8. There are three balls, one is red, one is yellow and one is green. They are put into three urns A, B and
C at random such that each urn will contain one ball. Find the probability that the green ball is in urn
C, the yellow ball is in urn B and the red ball is in urn A.

(P01C15L03Q009)
9. Two people are playing rock-paper-scissors. What is the probability that a single game ends with a
draw?

(P01C15L03Q010)
10. A tetrahedral die with numbers 2, 4, 6, 8 is rolled twice. Find the probability that the sum of the
numbers is
(a) an even number, (b) an odd number, (c) 10.

(P01C15L03Q011)
11. There are four F.1 classes in a school:
Class 1A 1B 1C 1D
No. of students 32 36 32 40
No. of students wear glasses 16 12 12 8
A F.1 student in the school is then chosen at random. Find the probability that the student does not
wear glasses.

(P01C15L03Q012)
12. A 3-digit number is formed by arranging 2, 3 and 4 at random. Find the probability that the number is
greater than 300.

(P01C15L03Q013)
13. Two dice are thrown. What is the probability that the sum of the two numbers is even if only one of
the numbers is ‘3’?

(P01C15L03Q014)

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Question Bank

14. Two dice are thrown. Find the probability that the sum is greater than 7 given
(a) there is a ‘4’,
(b) there is a ‘5’.

(P01C15L03Q015)
15. Two fair dice are thrown. Find the probability that the sum of the two numbers is
(a) a prime number,
(b) a multiple of 3,
(c) a prime number or a multiple of 3,
(d) neither a prime number nor a multiple of 3.

(P01C15L03Q016)
16. A dice is thrown three times. What is the probability of getting
(a) three ‘6’,
(b) no ‘6’,
(c) three even numbers.

(P01C15L03Q017)
17. One letter is chosen from each of the words ‘COOKIES’ and ‘CAKES’, find the probability that the
two letters chosen are vowels.

(P01C15L03Q018)
18. Mary is attempting three multiple choice questions. Each of them has five choices. If Mary answers
the questions by wild guessing, find the probability that she gets
(a) all correct,
(b) all wrong,
(c) exactly one question wrong.

(P01C15L03Q019)
19. The probability of getting a ‘3’ for a biased die is 0.2. If this biased die is thrown three times, find the
probability of getting
(a) three ‘3’, (b) no ‘3’, (c) exactly two ‘3’.

(P01C15L03Q020)
20. In playing the board game ‘Monopoly’, each player takes turn rolling the die. If a player rolls a ‘6’, he
is given another chance to roll the die. However, if a player rolls three ‘6’ consecutively, he has to
return to the starting point. Given that Nancy is playing ‘Monopoly’, find the probability that, in a
single turn, she

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 15More about Probability

(a) moves 10 blocks forward,

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Question Bank

Level 2 Questions

(P01C15L04Q001)
1. There are 4 exits in a school. Find the probability that two students, Tom and Susan, will not
use the same exit to enter and leave the school in a school day.

(P01C15L04Q002)
2
2. The chance of getting a head in tossing a biased coin is . If the biased coins is tossed twice, what is
5
the probability of getting
(a) two tails,
(b) one head and one tail.

(P01C15L04Q003)
3. Three dice are thrown. Find the probability that
(a) there are no even numbers,
(b) the three numbers are the same,
(c) there are at least two even numbers.

(P01C15L04Q004)
4. There are 5 red balls and 3 green balls in a bag. Balls are drawn one by one at random without
replacement until a green ball is drawn. Find the probability of getting a green ball in the
(a) first trial,
(b) third trial,
(c) fifth trial.

(P01C15L04Q005)
5. In a group of 6 students, what is the probability that at least two students having the birthdays in the
same month? (Assume that the probability for a student born in every month are the same, and give
your answer correct to 2 decimal places.)

(P01C15L04Q006)
6. One letter is chosen from each of the words ‘CERTIFICATE’ and ‘MATHEMATICS’, find the
probability that the two letters chosen are
(a) vowels,
(b) the same,
(c) different.

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 15More about Probability

(P01C15L04Q007)
7. There are four F.1 classes in a school:
Class 1A 1B 1C 1D
No. of students does not wear glasses 25 28 27 32
No. of students wear glasses 15 17 13 13
A F.1 class in the school is chosen at random, and a student is then randomly chosen. Find the
probability that the student does not wear glasses.

(P01C15L04Q008)
8. 20 balls numbered 1 to 20 are put in a box. Two balls are drawn at random without replacement. If the
number on the first ball drawn is a multiple of 4, find the probability that the number on the second
ball drawn is
(a) also a multiple of 4,
(b) a multiple of 7.

(P01C15L04Q009)
9. Three dice are thrown. What is the probability that the sum of the three numbers is even if only one of
the numbers is a ‘3’?

(P01C15L04Q010)
10. Three dice are thrown. It is known that at least one even number shows up. Find the probability that
the sum of the numbers is even.

(P01C15L04Q011)
3
11. Alan and Grace are playing basketball. The probability that Alan makes a shot is while that for
5
1
Grace is . Suppose each of them are going to shoot twice, find the probability that
3
(a) there is at least one shot made,
(b) there is exactly one shot made,
(c) there is at least two shot made.

(P01C15L04Q012)
12. The government recruitment examination consists of two parts, part I and part II. One has to pass the
part I examination in order to sit for the part II examination. John is going to apply for a government
3 1
job. The probability that John passes a examination on a sunny day is while on a rainy day is .
5 4

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Question Bank

2 1
Suppose the probability of a sunny day is and a rainy day is , find the probability that
3 3
(a) part I examination is held on a sunny day and John passes,
(b) John passes part I examination,
(c) John passes both parts of the examinations.

(P01C15L04Q013)
13. Calvin and Sarah are throwing two darts at a target respectively. In every shot, the probability that
3 1
Calvin hits the target is while that for Sarah is . If 1 point for a dart is hit and no point for a dart
5 4
is missed, find the probability that
(a) Calvin gets 1 point,
(b) Sarah gets 1 point,
(c) Calvin and Sarah get equal points,
(d) Sarah gets a higher point than Calvin.

(P01C15L04Q014)
14. There are two bags. Bag A contains 1 red marble, 1 blue marble and 2 green marbles. Bag B contains
2 red marbles and 2 blue marbles. Vincent chooses one bag at random and then a marble is drawn
randomly from the selected bag.
(a) Find the probability that the marble drawn is
(i) green,
(ii) red.
(b) Suppose Vincent puts the marble drawn from the selected bag into the other bag, and then
randomly draws a marble from that other bag. What is the probability that the second marble
drawn is of
(i) the same colour as the first marble,
(ii) different colours from the first marble.

(P01C15L04Q015)
15. Three light bulbs A, B, and C are connected in series in a circuit. The probabilities that the light bulbs
1 1 1
are defective are , and respectively.
2 3 4
(a) Find the probability that
(i) both light bulbs B and C are defective,
(ii) only light bulb A is defective.
(b) Given that the circuit does not work unless all the light bulbs are not defective, find the
probability that

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(i) the circuit works,

(P01C15L04Q016)
16. There are two aquariums of fishes. In aquarium A, there are 3 goldfish, 4 clown fish and 1 butterfly
fish. In aquarium B, there are 4 goldfish, 3 clown fish and 1 butterfly fish. Suppose a fish is randomly
picked from aquarium A and put into aquarium B, then two fish is picked at random one by one from
aquarium B and put into a new aquarium C. Find the probability that after the process,
(a) there is a butterfly fish in aquarium A,
(b) there is two butterfly fish in aquarium B,
(c) there is two butterfly fish in aquarium C,
(d) there is no butterfly fish in aquarium B.

(P01C15L04Q017)
17. A problem is solved independently by Alfred, Sam and Andrew. The probability that the problem can
4 1 3
be solved by them are , and respectively. Find the probability that
7 3 5
(a) all three of them can solve the problem,
(b) exactly one of them can solve the problem,
(c) the problem can be solved.
(d) If one of them are selected randomly to solve the problem, find the probability that the problem
can be solved.

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Question Bank

Level 2 Questions

(P01C15L05Q001)
1. A die is thrown three times. What is the probability that the three numbers obtained are consecutive
terms in an arithmetic sequence?

(P01C15L05Q002)
2. There are 3 boys and 3 girls sitting around a round table. What is the probability that no two girls are
sitting next to each other?

(P01C15L05Q003)
3. There are 9 black marbles and 1 white marble in a bag. Marbles are drawn one by one at random
without replacement until a white marble is drawn.
(a) Find the probability of getting a white marble in the
(i) first trial,
(ii) second trial,
(iii) fifth trial.
(b) If there are n black marbles and 1 white marble in the bag, find the probability of getting a white
marble in the
(i) first trial,
(ii) second trial,
(iii) nth trial.

(P01C15L05Q004)
4. Harry and Jane take turns throwing a dice. The one who first gets a ‘6’ will win the game. Suppose
Jane throws the dice first.
(a) Find the probability that Jane will win the game in her
(i) first trial,
(ii) second trial,
(iii) third trial.
(b) Find the probability that Jane wins the game in her nth trial.
(c) Find the probability that Jane will win the game.

(P01C15L05Q005)

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5. In a test, there are 4 multiple choice questions. Each question consists of 4 options. 1 mark will be
awarded for each correct answer, but 1 mark will be deducted for each wrong answer. Suppose Wendy
attempts all the questions by wild guessing, find the probability that she will get
(a) 0 mark,
(b) negative marks,
(c) at least 1 mark.

(P01C15L05Q006)
6. There are three fair coins, where one is a normal coin and two are two-headed coins. A coin is chosen
at random and tossed.
(a) Find the probability that a head shows up.
(b) If it is given a head shows up, what is the probability that the two-headed coin is tossed?
(c) If a head shows up, this chosen coin is tossed once more. If a tail shows up, a coin is chosen
randomly again from the three coins and tossed. Find the probability of getting
(i) two heads in these two trials,
(ii) two tails in these two trials.

(P01C15L05Q007)
7. There are 10 empty boxes. 5 balls are going to put one by one into a randomly selected box. Find the
probability that
(a) all the 5 balls are in 5 different boxes,
(b) all the 5 balls are in the same box,
(c) two of the boxes each contains 2 balls,
(d) one of the boxes contains 3 balls.

(P01C15L05Q008)
8. 20 balls numbered 1 to 20 are put in a box. Two balls are drawn at random without replacement. If the
number on the first ball drawn is a multiple of 4, find the probability that the number on the second
ball drawn is
(a) a multiple of 5, (b) a multiple of 8.

(P01C15L05Q009)
9. Five cards are drawn at random without replacement from a deck of 52 well-shuffled cards. Find the
probability of getting a hand of
(a) straight (A2345, 23456 or … or 10JQKA of any suits)
(b) flush (i.e. 5 cards of the same suit),
(c) straight flush (straight of the same suit).
(P01C15L05Q010)

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Question Bank

10. A factory producing computer chips has employed a QC checker. When a computer chip is defective,
the probability that the QC engineer identifies it (a true defective) is 0.95. When the computer chip is
not defective, the probability that the QC engineer identify as defective (false defective) is 0.02.
Suppose 0.5% of the computer chips produced is defective.
(a) Find the percentage of the computer chips that would show a
(i) true defective result,
(ii) false defective result.
(b) If a computer chip is identified as defective, what is the probability that it is a true defective?
(Give your answer correct to 3 significant figures.)
(c) If 1000 computer chips are produced each day, find the expected number of computer chips that
are falsely identified as defective? (Give your answer correct to the nearest integer.)

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Multiple Choice Questions

(P01C15L06Q001) 3
C.
4
1
1. In a class, there are 16 girls and 24 boys. 4
4 D.
5
3
of the girls and of the boys wear glasses.
8 (P01C15L06Q004)
If a student is selected at random, what is the 4. The probability of getting a head for a biased
probability that he/she wears glasses? 1
5 coin is . If that biased coin is tossed twice,
A. 3
8
find the probability of getting two tails.
3
B. 1
10 A.
27 9
C. 2
40 B.
13 9
D. 4
40 C.
9
8
(P01C15L06Q002) D.
9
2. In the World Cup Final between Brazil and
Italy, the probability that Brazil wins, Italy (P01C15L06Q005)
wins or a draw in 90 minutes are all equal. 5. The probability that Connie and Stephen will
Find the probability that no extra time is 1 3
be absent from school are and . Find
needed for the final. 4 8
1 the probability that neither of them are absent
A.
2
from school.
1
B. 3
3 A.
2 32
C. 5
3 B.
1 32
D. 9
4 C.
32
15
(P01C15L06Q003) D.
32
3. Five persons Tom, Peter, Jason, May and
Susan sit randomly around a round table. The
probability that May does not sit next to
Susan is
1
A.
2
2
B.
3

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Question Bank

(P01C15L06Q006) (P01C15L06Q009)
6. The probability that Paul, Kitty and Alice can 9. A bag contains 30 balls numbered 1 to 30.
1 2 3 Two balls are drawn without replacement.
finish a test in one hour are , and
2 3 4 Find the probability that both balls are
respectively. Find the probability that only divisible by 3.
Paul cannot finish the test. 1
A.
1 3
A. 1
3 B.
1 5
B. 3
4 C.
1 29
C. 10
6 D.
1 29
D.
12
(P01C15L06Q010)
(P01C15L06Q007) 10. There are 5 black marbles and 7 white
7. A fair die is thrown twice. Find the marbles in a urn. Two marbles are drawn
probability that the first number is a prime randomly one by one without replacement.
number and the second number is divisible by Find the probability that they are of the same
3. colour.
1 7
A. A.
6 22
5 5
B. B.
6 33
5 31
C. C.
36 66
13 35
D. D.
36 66

(P01C15L06Q008)
(P01C15L06Q011)
8. Two dice are thrown. Find the probability that
11. A shopkeeper has 10 keys, only one of which
the sum of the numbers is less than or equal
can open the shop. If the keys are chosen at
to 10.
random one by one without repetition, find
5
A. the probability that he can open the door in
6
11 less than 3 trials.
B.
12 1
23 A.
C. 5
24 1
35 B.
D. 9
36 1
C.
10
19
D.
90

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 15More about Probability

(P01C15L06Q012)
12. An aeroplane has four engines. The plane can (P01C15L06Q015)
operate with at least one engine. Suppose all 15. There are 5 questions in a test. 3 of them are
the engines work independently and each true-or-false questions and 2 of them are
engine has the probability of 0.1 to be multiple choice questions with 4 options. If
malfunction. Find the probability that the Billy answers all the questions by wild
plane can operate. guessing, find the probability that he gets
A. 0.0009 only one answer wrong.
B. 0.0099 3
A.
C. 0.0999 32
3
D. 0.9999 B.
64
3
C.
(P01C15L06Q013) 128
9
13. Two dice are thrown. If the two numbers are D.
128
both even, find the probability that the sum of
the two numbers is 6. (P01C15L06Q016)
1
A. 16. In a class, 40% of the students are girls.
3
1 Given that 25% of the girls and 37.5% of the
B.
6 boys are choir members. If a student is
1 chosen at random, find the probability that the
C.
9
student is NOT a choir member.
2
D. A. 0.3
9
B. 0.325
(P01C15L06Q014) C. 0.675
14. There are 3 fair coins where one is a two- D. 0.7
headed coin and two are normal coins. If a
coin is chosen at random and tossed one, find (P01C15L06Q017)
the probability of getting a head. 17. A parachutist is landing on a circular target of
1 100 m in diameter. What is the probability
A.
2 that he is within 20 m from the centre of the
5
B. target?
9
2 1
C. A.
3 5
5 1
D. B.
6 25
4
C.
25
16
D.
25

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