Question

Mary has scored 78 , 60 , 82 , 94 , and 88 on her previous five tests . What score does she need on her next test so that her average ( mean ) is 80?​

Answer 1

She needs to score 78 on her next test

Explanation:

`(78+60+82+94+88+x)/(6)=80`

Collect like terms;

`(402+x)/(6)=80`

Multiply both sides by 6;

402 + x = 480

Subtract 402 from both sides;

x = 78