Permutation and Combination

How many five digits numbers divisible by 5 can be formed from digits 2, 1, 0, 7, 5 if the digits are not to be repeated?

A child is asked to pick four coins from a bag containing one coin each of Re. 1, 50p, 25p 10p, 5p, 2p and 1p coins. How many different combinations of the coins can he pick?

5 people are to be arranged in a circle. Find the number of ways such that two particular persons never stand together.

Find the number of squares on a chessboard?

How many three-digit numbers divisible by 3 can be formed out of the digits 3, 4, 5 and 6 if the digits are not to be repeated?

Out of 2 Women and 5 Men, a committee of 3 is to be formed. In how many ways can it be formed if at least one woman is to be included in the committee?

How many words can be formed from the letters of the word "ENGINEERING", so that vowels always come together?

How may four-digit numbers can be made out of the digits 1, 2, 3 and 9 which are less than 3000, if repetition of the digits allowed?

In how many ways, 6 girls may be selected for a team out of 12 girls in a class so that 2 particular girls (captain and vice-captain) are always there in the team?

A box contains 2 white balls, 5 black balls and 4 red balls. In how many ways can 3 balls be drawn from the box, if at least one black ball is to be included in the draw?