After 4 tests Amanda's average score was 88. What score must she earn on her next test to have a 5 test average of 90

Question

Please show me how to figures out the problem 

Answer 1

let n=the score on her next test

(88+88+88+88+n)/5=90

(352+n)/5=90

352+n=5*90

352+n=450

n=450-352

n=98 is needed on the next test

 

you can solve the problem using simple arithmetic...

she is already 2 points behind on each of 4 tests (she has basically 4 88's)

4*2=8 plus 90 equals 98