There are four balls of different colours and four boxes of colours same as those of the balls. Find the number of way in which the balls ,one in each box,of its own colour.

There are 4 balls of different colours and four boxes of colours same as these of the balls the number of ways in which the balls one in each box would be placed such that a ball does not go to a box of its own colour is

There are 5 different colour balls and 5 boxes of colours same as those of the balls. The number of ways in which one can place the balls into the boxes, one each in a box, so that no ball goes to a box of its own colour is

There are greetings cards, each of a different colour and 7 envelopes of same 7 colours as that of the cards. The number of ways in which the cards can be put in envelopes, so that exactly 4 of the cards go into envelopes of respective colour is,

The number of ways of painting the faces of a cube with six different colours is

There are 2 identical white balls, 3 identical red balls, and 4 green balls of different shades. Find the number of ways in which they can be arranged in a row so that atleast one ball is separated from the balls of the same color.

No.of ways to distribute n balls into r boxes is

A bag contains 5 black and 6 red balls. Determine the number of ways in which 2 black and 3 red balls can be selected.

Fifteen identical balls have to be put in five different boxes. Each box can contain any number of balls. The total number of ways of putting the balls into the boxes so that each box contains at least two balls is equal to a. .^9C_5 b. .^10 C_5 c. .^6C_5 d. .^10 C_6

Out of 20 different pearis, if there are 10 pearls of each colour, then the number of ways in which two colours can be set alternately on a necklace, is

There are two bags each of which contains n balls. A man has to select an equal number of balls from both the bags. Prove that the number of ways in which a man can choose at least one ball from each bag is^(2n)C_n-1.