Question

In how many ways three different rings can be worn in four fingers with at most one in each finger ?

Answer 1

The total number of ways is same as the number of arrangements of 4 fingers, taken 3 at a time.

So, required number of ways = $4_{P_3}=\frac{4!}{(4-3)!}=\frac{4!}{1!}=4!=24$