Question

Find the number of ways in which a person can invite his 4 friends selecting at least one.

Answer 1

here is ur answer:

he cn invite either 1, 2, 3 or all 4 frds

so, the no. of ways he cn invite is 4!

4! = 4 × 3 × 2 × 1

4! = 24

hope it helps you!