Over the last three evenings, Maria received a total of 129 phone calls at the call center. The second evening, she received 4 times as many calls as the third evening. The first evening, she received 9 more calls than the third evening. How many phone calls did she receive each evening

Step-by-step explanation:

Since the problem description tells you the numbers in terms of the calls received on the third evening, let that value be represented by x. Then we have ...

  first evening's calls: x + 9

  second evening's calls: 4x

  third evening's calls: x

  Total calls = 129 = (x +9) +4x +x = 6x +9

  x = (129 -9)/6 = 20

Maria received 29 calls the first evening, 80 calls the second evening, and 20 calls the third evening.