Question

John´s test scores for this marking period are: 72, 84, 86, and 70. What score must John get on his next test to maintain an average of 80?

Answer 1

John must get the next score of 88 to maintain the average score of 80

Step-by-step explanation

Given Test scores: 72,84,86,70

We need to find the next test score such that the average score becomes 80

So let the next test score b x

Now the average test score can be found as

Average test score=
`(72+84+86+70+x)/(5)`

⇒80=
`(72+84+86+70+x)/(5)`

⇒80=
`(312+x)/(5)`

⇒80∗5 = 312+x

⇒400=312+x

⇒400−312=x

⇒x=88

Therefore, John must get the next score of 88 to maintain an average score of 80

Answer 2

88

Explanation:

Go backwards with the question. So you start by multiplying 80 by 5, you get 400. Subtract the numbers you know from 400. You get 88