Four books, one each in Chemistry, Physics, Biology and Mathematics, are to be arranged in a shelf. In how many ways can this be done?

In how many ways can 4 different books, one each in chemistry, physics, biology and mathematics, be arranged on a shelf?

There are 10 different books in a shelf. In how many ways we can select atleast one of them ?

There are three different rings to be worn in four fingers with at most one in each finger. In how many ways can this be done?

8 identical book are to be place in 4 identical shelf. Find the number of different ways can be done

In how many ways can 7 different books be arranged on a shelf? In many ways three particular books are always together?

A library has two books each having three copies and three other books each having tow copies. In how many ways can all these books be arranged in a shelf so that copies of the same book are not separated.