Question

The digits 1, 7, and 8 and 2 copies of the digit 5 are all arranged to form a 5-digit integer. How many different integers can be formed?

Answer 1

Explanation:

You have 5 digits.Youdonot say if duplication is allowed. I will assume not

For the first digit you have 5 choices. One of the 5 digits is gone.

You now have 4 digits to choose from. You pick one. Now you have but 3 left.

The total answer if 5*4*3*2*1 = 120