Solving a word problem with three unknowns using a linear equation

Question

Over the last three evenings, Ashley received a total of 85

 phone calls at the call center. On the third evening, she received 2

 times as many calls as the second evening. The first evening, she received 5

 more calls than the second evening. How many phone calls did she receive each evening

Answer 1

Let A = Number of calls received in the first evening

      B = Number of calls received in the second evening

      C = Number of calls received in the third evening

Given:

A + B + C = 85

C = 2B

A = B + 5

Since both A and C are functions of B, we substitute those functions into the first equation.

(B+5) + B + 2B = 85

4B = 80

B = 20

From that, we get

A = 25

C = 40

Therefore, Ashley received 25 calls the first night, 20 calls the second night, and 40 calls the third night.