Mele earned scores of 75, 70, 92, 95, and 97 points (a total of 429 points) on the first 5 tests in Economics II. Solving which of the following equations for s gives the score he needs to earn on the 6th test to average exactly 85 points for all 6 tests?

- 429/5 + s = 85
- 429/6 + s = 85
- (s + 429)/5 = 85
- (s + 429)/6 = 85
- (s + 429)/6 = 85/100

**The correct answer is D.**

Let s represent the score on the sixth test. Then, the average score on the 6 tests is equal to (75 + 70 + 92 + 95 + 97+ s)/6.

= (s + 429)/6