Let Tn denote the no. of triangles which can be formed using the vertices of a regular polygon of n sides. If T(n+1) -Tn = 21 , then the value of n is
5
7
6
4
In how many ways can 4 boys and 3 girls be seated in a row of 7 chairs, if the boys and girls have to sit alternate?
80
120
144
288
In a party , 12 persons are to be arranged in a round table. If two particular persons are not to sit side by side, then the total no. of arrangements is
9 x 10!
2 x 10!
45 x 8!
10!
The no. of diagonals of a polygon of n sides is
n (n-1)/2
n (n-2)/2
n(n-3)/2
n (n-5)/2
The no. of way in which the letters of the word 'ARRANGE' can be arranged such that both 'R' do not come together is
360
900
1260
1620
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
A father with 8 children take 3 at a time to a zoological garden. If the father without taking the same 3 children more than once, then the no. of times he will go to the garden is
336
112
56
28
The no. of 5 digit numbers that can be formed with the digits 0,1,2,3,4 if the numbers can be repeated in the same number is
25
250
2500
12500
If 10Pr = 9P5+5. 9P4, then the value of r is
2
3
8
The no. of ways in which a committee of 5 members can be selected from 6 men and 5 women consisting of 3 men and 2 women is
100
200
300
400