lennys average score after 3 tests is 88.What score on the 4th test would bring lennys average up to exactly 90?

Answer 1

Hi, Davianna,

If Lenny's average over 3 tests is 88, three times 88 would be his total points, thus far, or 264 points. He needs to add X points to his score on the forth test to make it an average for all 4 tests of 90.

So write an equation of total points (264 + X) and divide that by the number of tests to get the higher average of 90:

I hope that helps,

Bob

Answer 2

To get an average, you add up all the scores and divide by the number of tests.

Let x be the score on the 4th test. We don't know the exact scores on the other tests. Since we know the average is 88, we can use 88 for all of them.

(88+88+88+x)/4 = 90 Simplify

(264+x)/4 = 90 Multiply by 4 to get rid of the fraction

(264+x)/4(4) = 90(4) Simplify

264+x = 360 Subtract 264 from both sides

264+x-264 = 360-264

x=96 on the test to bring his average up to a 90