How many selection of 4 books can be made from 8 different books?

How many different selection of 4 books can be made from 10 different books, if (i) Two particular books are always selected. (ii) Two particular books are never selected.

How many different selections of 4 books can be made from 10 different books, if There is no restriction; Two particular books are always selected; Two particular books are never selected?

How many different selections of 6 books can be made from 11 different books, if (i) two particular books are always selected. (ii) two particular books are never selected?

How many different signals can be made from 4 red, 2 white and 3 green flags by arranging all of them vertically on a flagstaff?

How many balls, each of radius 1 cm, can be made from a solid sphere of lead of radius 8 cm?

How many balls, each of radius 1 cm, can be made from a solid sphere of lead of radius 8 cm?

George is going on vacation and wishes to take along 2 books to read. If he has 5 different books to choose from, how many different combinations of 2 books can he bring ?

In how many ways can 4 books be chosen from 12 books if (i) there is no restriction? (ii) a particular book is always included? (iii) a particular book is never included?

How many different signals can be made by 5 flags from 8 flags of different colours?

How many different signals can be made by 5 flags from 8 flags of different colours?