From 10 boys and 20 girls, a committee of 2 boys and 3 girls is to be formed. In how many ways can this be done if a particular boy is included

From 10 boys and 20 girls, a committee of 2 boys and 3 girls is to be formed. In how many ways can this be done if a particular girl is included

From 10 boys and 20 girls, a committee of 2 boys and 3 girls is to be formed. In how many ways can this be done if a particular girl is excluded.

In how many ways can one post 3 letters in 5 post boxes?

There are 7 boys and 3 girls in a class. In how many ways can they be arranged in a row such that no two girls are together?

In how many different ways can one invite 3 or more of his 6 friends?

In how many ways can a selection of 4 be made from 10 persons such that one particular person is always included

In how many ways can a selection of 4 be made from 10 persons such that one particular person is always excluded?

Work Problem on Time and Work Nine boys and four girls complete a piece of work in four days. Two boys and four girls complete that work in ten days. How much time does a boy or a girl alone need to complete the work.

How many different committee of four members can be formed out of eight players?

In how many, ways can 5 boys and 5 girls be placed in a circle,so( that no two boys are side by side?