Question

Steve has these score on the exams for this semester: 89, 92, and 87. How much will have to make on the fourth exam to have a final average of an A (a 92% or better)?

Answer 1

so

89 + 92 + 87 + x
---------------- = 92
4

multiply both sides by 4

89 + 92 + 87 + x = 368


isolate x

89 + 92 + 87 + x = 368
-89 - 92 - 87 -(those totaled)

x = 100

So Steve will need a 100 on the exam to get an average of 92