Question

Jake's test scores are 86, 70, 72, 100, 96, and 80. What must Jake earn of his last test to earn a mean grade of exactly 85%?

Answer 1

91

Explanation:

Mean is calculated as

mean =
`(sum)/(count)`

let x be his test score of his last test , then

`(86+70+72+100+96+80+x)/(7)` = 85 ( multiply both sides by 7 )

504 + x = 595 ( subtract 504 from both sides )

x = 91