Permutation & Combination

1

Out of 7 consonants  and 4 vowels , how many words of 3 consonants and 2 vowels can be formed ?

A. 210
B. 1050
C. 25200
D. 21400
E. None of these.

2

In how many ways can 21 books on English and 19 books on Hindi be pleaced in a row on a shelf so hat two books on Hindi may not be together ?

A. 3990
B. 1540
C. 1995
D. 3772
E. None of these

3

How many 3-digit number can be formed from the digits 2, 3, 5, 6, 7 and 9 , which are divisible by 5 and none of the digits is  repeated ?

A. 5
B. 10
C. 15
D. 20

4

A box contains 2 whits balls , 3 black balls and 4 red ball . In how many ways can 3 balls be drawn from  the box , if at least one black ball is to be included in he draw ?

A. 32
B. 48
C. 64
D. 96
E. None of these

5

In a group of 6 boys and 4 girls , four children are to be selected . In how many different ways can they be selected such that at least one boy should be there ?

A. 159
B. 194
C. 205
D. 209
E. None of these .