Linear inequalities application

Question

A student scores 71 out 100 on a test. If the maximum score on the next test is also 100 points, what score does the student need to maintain at least an average of 78? 

Answer 1

s represents the score on the second test

 

(71 + s) / 2 = 78      multiply both sides by 2

71 + s = 156              subtract 71 from both sides

s = 85

 

The student needs an 85 of the second test to maintain a 78 average.