Question

A student scored 83 and 91 on her first two quizzes. Write and solve a compound inequality to find the possible values for a third quiz score that would give her an average between 85 and 90, inclusive

Answer 1

Explanation:

3*85 <= 83+91+x <= 3*90

255 <= 174+x <= 270

81 <= x <= 96

Answer 2

81 ≤ x ≤ 96

Explanation:

85 ≤ (x + 83 + 91)/3 ≤ 90

85 ≤ (174 + x)/3, (174 + x)/3 ≤ 90

81 ≤ x ≤ 96