16Hit1600
AlgebraHardLeast third score for a target average

Algebra practice question

A student's first two test scores are 70 and 85. What is the least score on a third test that would make the average of the three scores at least 80?

Answer: 85

(70 + 85 + x)/3 ≥ 80 gives 155 + x ≥ 240, so x ≥ 85.

Common wrong answers

If you answered 75
75 is the average of the first two, not the required third score.
If you answered 80
80 gives an average of 78.3.
If you answered 95
95 is more than needed.

More Algebra questions

Not affiliated with the College Board. SAT is a trademark of the College Board.