Question

In how many ways five different rings can be worn in four fingers with at least one ring in each finger?
A. 120
B. 96
C. 20
D. 480

Answer 1

Since at least one ring is to be worn in each finger. So, we first select four rings out of 5 given rings and then they are arranged in fingers. This can be done in `""^(5)C_(4)xx4!` ways.
Now, one ring is left which can be worn in any one of the four fingers in 4 ways.
Hence, required number of ways `=""^(5)C_(4)xx4!xx4=480`.