Question

On three of the first four math tests, Daniel earned the following scores: 84, 92 and 88. If Daniel’s

average for all four tests is 87.5, what score did Daniel earn on his fourth test?

Answer 1

Answer: 86

Explanation:

let x be the unknown

(84+92+88+ x)

----------------------- = 87.5

4

then cross multiply

(84+92+88+ x )= 87.5 times 4

84+ 92+ 88 + x= 350

add the left side

264+ x=350

subtract 264 from both sides

264 - 264 + x= 350 - 264

therefore x= 86.