in order to qualify for her High School honor roll Janet must have a test average of 90 as of right now she has test scores of 88, 94, 81, 96, and 82. She has on test left this marking period. what is the minimum grade she must earn on the last test to qualify for the honor roll?

Answer: 99

Explanation:

The formula for average is (sum of all numbers) / (the count of the numbers)

For example, as of right now, her average is:

(88+94+81+96+82) / 5 = 88.2

Let's say she's wants a 90. And there's only another test left. We are trying to find out what her last text score needs to be:

Let x be her last test score

88+94+81+96+82+x) / 6 = 90

Multiply both by 6

(88+94+81+96+82+x) = 540

441+x = 540

Subtract 441 on both sides:

x=99

She needs to get a 99 if she wants an average of 90. She better start studying!