Question

Marsha’s scores on seven tests were: 82, 78, 77, 93, 85, 91, and 86. What does she need to score on her next test to have an 86 average?

Answer 1

Answer:

The score of her next test  is 96

Step-by-step explanation:

If there is a set of data with x terms, then the average is the sum of their values divided by x

Average = sum of values of the x terms ÷ x

We will use this rule to solve the question

∵ Marsha's scores on 7 test were 82, 78, 77, 93, 85, 91, 86

→ Find her total scores on the seven tests

∴ Her total scores = 82 + 78 + 77 + 93 + 85 + 91 + 86 = 592

∴ Her total scores on the 7 tests is 592

∵ Her average score on the 8 test is 86

→ Use the rule of the average to find her total score in the 8 test

∵ 86 = total scores ÷ 8

→ Multiply both sides by 8

∴ 86 × 8 = total scores × 8 ÷ 8

∴ 688 = total scores

∴ Her total scores on the 8 tests is 688

∵ Her total scores on the 7 test = 592

∵ Her total scores on the 8 test = 688

→ The difference between both totals is the score of her next test

∴ The score of her next test = 688 - 592 = 96

∴ The score of her next test  is 96