Answer:
90
Step-by-step explanation:
The mean is measured as
mean = [tex]\frac{score}{count}[/tex]
After 5 tests the mean is 84, that is
[tex]\frac{score}{5}[/tex] = 84 ( multiply both sides by 5 )
score = 420
let the sixth test score be x, then
[tex]\frac{420+x}{6}[/tex] = 85 ( multiply both sides by 6 )
420 + x = 510 ( subtract 420 from both sides )
x = 90
Require to score 90 on the sixth test
