Worded Problems Involving Inequalities

Question

John wants to have at least an 80% grade average in his math class. His quarterly grades so far are 85, 75, and 78. What is the lowest he can make on his fourth-quarter grade and still have an 80% test average?

Answer 1

(85+75+78 + x)/4 = 80

238 + x= 320

x = 320-238 = 82

He needs at least an 82 to have an 80 average.

85 and 75 have an 80 average

78 and 82 also have an 80 average.