Question

Alan has forgotten his 4-digit PIN code.

He knows it begins with a 7 and the 4 digits make a number divisible by 5.
How many different sets of 4 digits could it be?

Answer 1

200

Explanation:

If the number is divisible by 5, then the last digit should be either 5 or 0.

First digit is fixed.

Second digit can be 10 ways.

Third digit can be 10 ways.

Fourth digit can be 2 ways.

So total number of digits 1 x 10 x 10 x 2 = 200