In how many ways can 3 men and their wives be made stand in a line such that none of the 3 men stand in a position that …

A teacher of 6 students takes 2 of his students at a time to a zoo as often as he can, without taking the same pair of c…

How many diagonals can be drawn in a pentagon?

There are five women and six men in a group. From this group a committee of 4 is to be chosen. How many different wa…

After every get-together every person present shakes the hand of every other person. If there were 105 handshakes in all…

There are 10 points in a plane out of which 4 are collinear. Find the number of triangles formed by the points as vertic…

In how many different ways can the letters of the word ALLAHABAD be arranged?

In how many ways can 10 examination papers be arranged so that the best and the worst papers never come together?