Question

Ella’s test grades in her history class are 89, 94, 82, 84, and 98. What score must Ella make on her next test to have a mean test score of 90?

Answer 1

the answer is 93

Explanation:

mean of x,y,z

x+y+z

3 terms

(x+y+z)/3=mean

so

represent next test score as x

89+94+82+84+98+x

count how many terms ther are (6 terms)

mean is 90

(89+94+82+84+98+x)/6=90

add the like terms

(447+x)/6=90

multiply both sides by 6 to clear fraction

447+x=540

subtract 447 from both sides

x=93