Question

1. Get-A-Great-Read Books is adding a new phone line.

The phone company says that the first 3 digits of the
phone number must be $55, but the remaining 4 digits,
where each digit is a digit from 0 through 9, can be
chosen by Get-A-Great-Read Books. How many phone
numbers are possible?
A. 5(94)
B. 53(94)
C. 53(104)
D. 94
E. 104

Answer 1

E. 10^4

Explanation:

The first 3 digits are fixed.

There are 10 possible numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) for each remaining 4 digits. Therefore, there are 10*10*10*10 = 10^4 ways to fill the last 4 digits, or 10^4 possible phone numbers.