Sarah received scores of 85, 92 and 78 on her first three exams of the grading

period. What is the lowest score Sarah can earn on the next exam for the exam

average to be at least a 87 for the grading period.

92

Step-by-step explanation:

The total Score is 85 + 92 + 79 + x = 4 * 87

The total Score needed is 4 * 87 = 348

So to get that score we need to add the other scores up

256 + x

which equals the total of the 4 tests.

256 + x = 348

Subtract 256 from both sides.

256 - 256 + x = 348 - 256

x = 92 Pretty high, but doable.