Answer:
90
Explanation:
The mean is measured as
mean =
![(score)/(count)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zgitygzqv4mr9mx3u7vyh8npqx0wwnkykx.png)
After 5 tests the mean is 84, that is
= 84 ( multiply both sides by 5 )
score = 420
let the sixth test score be x, then
= 85 ( multiply both sides by 6 )
420 + x = 510 ( subtract 420 from both sides )
x = 90
Require to score 90 on the sixth test