A student scored 80 in 2 tests and 90 in 3 tests. What is the average of all 5 scores?
Correct answer: C. 86
Total = 2 × 80 + 3 × 90 = 160 + 270 = 430. Average = 430 ÷ 5 = 86. Averaging 80 and 90 to get 85 is wrong because there are more scores of 90.
hard