QA Odds
Odds in favour of An Event and Odds Against An Event
In m be the number of ways in which an event occurs and n be the number of ways in which
it does not occur, then
(i)
odds in favour of the event =
(ii)
odds against the event =
(or m : n)
(or n : m)
Solved Examples:
1) 3 shooters A, B, C are hitting a target. Odds are 1 : 2 in favour of A, 1 : 2 in favour of
B & 2 : 3 against C hitting the target.
Answer:
Odds are 1 : 2 in favour of A
Odds are 1 : 1 in favour of B
Odds are 2 : 3 against C
P A 1
3
2
P ' A
3
P B 1
2
P ' B 1
2
PC 3
5
2
P' C
5
a) Find the probability that all three will hit the target.
1/3 x x 3/5 =
1
10
b) No one will hit the target.
2/3 x x 2/5 =
2
15
c) The target will be hit.
1 - 2/15
13
15
d) Find the probability that exactly 2 will be hit. A and B but not C= 1/3 x x 2/5 = 1/15
A and C but not B= 1/3 x x 3/5= 1/10
B and C but not A = 2/3 x x 3/5 = 1/5
Exactly two = 1/15 + 1/10 + 1/5 = 11 30
Proprietary and Confidential
ABS Classes
QA Odds
Proprietary and Confidential
ABS Classes