If nCr, denotes the no. of combinations of n things taken r at a time, then the value of expression
nC(r+1) +rC(r-1)+ 2nCr is
(n+2)Cr
(n+2) C(r+1)
(n+1) Cr
(n+1) C(r+1)
In how many ways can 21 English and Hindi books be placed in a row, so that not two Hindi books are together?
1540
1450
1504
1405
In how many ways 6 persons can stand in a queue at a time?
120
240
480
720
How many no. of 6 digits can be formed from the digits of the number 112233?
30
60
90
How many three -letter words can be formed from the alphabets a, b, c, d and e, if repetition is not allowed?
5
25
100
The no. of words that can be formed out of the letters of the word ARTICLE, so that the vowels occupy even places, is
574
36
754
144
If 2nP3= 2. nP4, then the values of n is
4,5
6,10
1,8
2,4
Seven athletes are participating in a race. In how many ways the first three prizes can be won?
220
210
200
180
A polygon has 44 diagonals. The no. of its sides is
11
7
8
It is required to seat 5 men and 4 women in a row, so that women occupy the even places. How many such arrangements are possible?
9
20
2880