Question

The mean weight of the packages Joan shipped was 2.5 pounds. If Joan mailed four packages and three of them had weights of 1.7, 3.2, and 2.8 pounds, then what did the other package weigh?

2.3
2.8
3.3

Answer 1

(1.7 + 3.2 + 2.8 + x) / 4 = 2.5
(7.7 + x) / 4 = 2.5.....multiply both sides by 4, eliminating the /4
7.7 + x = 2.5 * 4
7.7 + x = 10
x = 10 - 7.7
x = 2.3 <====