After five tests Allison's average score was 88. After six tests her average score had increased to 90. What was her score on the sixth test?

Sixth test was 100

Step-by-step explanation:

5 tests average is 88 - An equation for the average is ...

5x/5 = 88 (where x is 88) so it can also be 440/5 = 88 and this is correct

The sixth test has to be greater than 88 as the average increases; an equasion for this is ...

Let y = the sixth test result

Let x = the previous average; 88

(5x + y) / 6 = 90 (the new average)

5x + y = 540

As said before 5x = 440 so we can substitude 440 into 5x

440 + y = 540 (-440)

y = 100

So, the equation shows that the 6th test result is 100 but we should check to see if this is correct so ...

440 + 100 = 540

540 / 6 = 90 (so we are correct!)

100

Step-by-step explanation:

After five test, Allison's average score was 88. Let the total of her score be x

x/5=88

Cross multiply

x=88 (5)

x=440

The total scores of the five test was 440.

After the sixth test, her acreage score became 90. Let the total score again be x

x/6=90

Cross multiply

x=90 (6)

x=540

The sixth score is 540-440=100