Class-XI                                                          Permutations and combinations
1. In how many ways can the letters of the word ‘ARRANGE’ be arranged such that the two R’s do
       not occur together.
   2. How many 9-digit numbers of different digits can be formed
   3. How many four digit even integers can be formed using the digits 0,1,2,3,4,5
   4. How many 2-digit numbers can be formed from the digits 8,1,3,5and 4 assuming
       (a) Repetition of digits is allowed               (b)Repetition of digits is not allowed
   5. From the digits 1,2,3,4,5,6, how many three digit odd numbers can be formed when the repetition
       of the digits is not allowed
   6. (i) How many different words can be formed with the letters of the word “BHARAT”
       (ii) In how many of these B and H are never together
       (iii) How many of these begin with B and end with T
   7. (i) How many different arrangements can be formed with the letters of the word
       “MATHEMATICS”
       (ii) In how many of them vowels occur together
   8. In how many ways can the letters of the word “COMBINE” be arranged so that
       (i)      The vowels are never separated
       (ii)     All the vowels never come together
       (iii)    Vowels occupy only odd places
   9. There are 5 blue balls and 3 green balls. In how many ways they can be arranged in a row so that
       no two green balls are together
   10. How many add numbers less than 1000 can be formed using the digits 0,2,5,7 where
   (i)       Repetition is allowed               (ii) Repetition not allowed
   11. Ten different books are arranged on a shelf. Find the number of different ways in which this can be
       done, if two specified books are (a) together              (b) not together
   12. In how many ways can 20 books be arranged on a shelf so that a particular pair of books shall not
       come together
    13. If   (a) 4 P =n ( 4C ) , find n
                   2        2
                                          (b) nC :nC =1:2 and nC : nC =2 :3 find the values of n and r
                                               r   r +1          r+1   r+ 2
    14. A committee of 4 is to be selected from amongst 5 boys and 6 girls. In how many ways can this be
        done so as to include at least one girl
    15. How many different words, each containing 2 vowels and 3 consonants, can be formed with 5
        vowels and 17 consonants
    16. Find the number of (a) combinations,(b) permutations of four letters taken from the word
        EXAMINATION
    17. In how many ways can we a cricket eleven from 17 players in which 5 players can bowl, if each
        cricket team should include 2 bowlers
    18. A committee of 5 is to be formed from a group of 12 students consisting of 8 boys and 4 girls. In
        how many ways can the committee be formed if it
        (i)Consists of exactly 3 boys and 2 girls (ii) contains at least 3 girls
    19. A committee of 5 persons is to be formed from a group of 6 gentlemen and 4 ladies. In how many
        ways can this be done if the committee includes at least one lady
    20. Out of 3 books on Economics, 4 books on Political Science and 5 books on Geography, how many
        collections can be made, if each collection consists of
        (i)Exactly one book of each subject       (ii) at least one book of each subject