Question

So far in math class, a student's quiz scores are 86%, 82%, 72%, and 69%. What score does the student need on the fifth quiz to have a mean quiz score of 79%? All the quizzes have equal weights. a 86% b 77.25% c 79% d 87%

Answer 1

a

Explanation:

the mean =
`(total score)/(count)`

let the fifth score be x and count = 5, hence

`(86+82+72+69+x)/(5)` = 79 ( multiply both sides by 5 )

309 + x = 395 ( subtract 309 from both sides )

x = 86

the student requires a score of 86% → a