Question

Rhonda would like to call her coworker Jessica, but she only remembers the first three digits of the seven-digit telephone number, and that the last four digits are all even numbers. What is the maximum number of calls Rhonda must make to dial the correct number for Jessica if the last four digits are all different?

Answer 1

Answer:

120 calls

Explanation:

A phone number has 7 digits, of which we know three, leaving 4 spaces left.

Those four spaces are all different even numbers. Even numbers of only one digit include: 0,2,4,6,8. In total there are 5 options.

So the equation is simply multiply 5 x 4 x 3 x 2 = 120.