Question

A student has taken three tests and earned an 85, 80, and 75. She will take one more test comprised of 20 questions. Each question is worth 5 points. The student would like to have a test average of at least 87. What grades on the fourth test will I've her this average?

Answer 1

(85 + 80 + 75 + x) /4 = 87

(240 + x) /4 = 87

240 + x = 348

x = 108

She needs a 108 in order to have the test average of 87.

(85 + 80 + 75 + 108)/4 = 87

348/4 = 87

87 = 87