# Key made scores of 81, 76, 82 on three quizes. what is the least she can make on the fourth quiz to have an average of at least 80?

2
by tisangD

## Answers

2014-11-17T12:18:43+08:00

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
The formula for this will be

(81 + 76 + 82 + x)4 = 80

Where x will be the score of his 4th quiz

let's solve

239 + x/4 = 80

Multiply both by 4 to eliminate fraction

(239 + x/4)4 = 80 * 4

239 + x = 320

Transpose 239 to get the value of x. Then subtract

x = 320 - 239

Therefore

x = 81

That means he need a score of 81 or above to have at least an average of 80.

I hope it helps
2014-11-17T22:49:08+08:00

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
(81+76+82+x)/4=80
81+76+82+x=320
239+x=320
x=81