A cricket team consisting of 11 players is to be chosen from 8 batsmen and 5 bowlers. In how many ways can the team be chosen so as to include at least 3 bowlers ?

A bag contains 4 black and 5 white balls out of which 6 balls are drawn arbitrarily. In how many ways can this be done? Find also the number of ways such that at least 3 black balls can be drawn .

In how many ways can 2 boys and 3 girls sit in a row so that no two girls sit side by side?

A bag contains 5 white and 3 black marbles and a second bag contains 3 white and 4 black marbles. A bag is selected at random and a marble is drawn from it. Find the probability that it is white. Assume that either bag can be chosen with the same probability.

How many 2.5 kg bricks can a man carry up a staircase 3.6m high in one hour if he works at the average rate of 9.8 watt ?

If you throw a pair of dice n times, find the probability of getting at least one doublet.[When you get identical members you call it a doublet. You can get a double in six ways: (1,1),(2,2),(3,3),(4,4),(5,5) and (6,6) , thus the probability of getting a doublet is 6/36=1/6 , so that the probability of not getting a doublet in one throw is 5/6] .