Local Phone number Question

Question

Local phone numbers consist of seven numerals, the first three of which are common to many users A small town's phone numbers all start with 318 , 329, or 357. How many phone numbers are available ?

Answer 1

Miguel, this is just a question of counting the possible numbers.

The 1st 3 digits are 318 , 329, or 357 => 3 choices.

The remaining 4 digits can be anything from 0000 to 9999 => 10,000 choices.

Therefore, there is a total of 3 x 10,000 = 30,000 numbers, available.