Question

A student scored an 88, 92, and 76 on three math tests. What does the student need to get on the fourth test to have an average of 85 for all four tests?

James wants to use algebra to solve this problem. Which equation should he use?

Answer 1

average of 4 tests is 85
last test is x the one he needs

`(88+92+76+x)/(4)=85`
times 4 both sides
88+92+76+x=340
256+x=340
minus 256 from both sides
x=84

he has to get 84


he should use
`(88+92+76+x)/(4)=85`

Answer 2

Answer: The student need to get 84 marks in the fourth test to have an average of 85 for all four tests

Explanation:

Since we have given that

Scores of a student were

88, 92, 76 on three math tests.

Since we want an average of 85 for all four tests.

Let the score he get on fourth test of Math be x.

As we know the formula for " Average" :

`Average=\frac{\text{ Sum of all observation }}{\text{ Total number of observation }}\\\\85=(88+92+76+x)/(4)\\\\85* 4=88+92+76+x\\\\340=256+x\\\\340-256=x\\\\84=x`

Hence, The student need to get 84 marks in the fourth test to have an average of 85 for all four tests.