SOLUTION: On her last three quizzes Elise scored 84 96 and 88. What grade must she get on her next quiz to have an average of 90 for all for quizzes ? Thank you ! (:

Question 526739: On her last three quizzes Elise scored 84 96 and 88. What grade must she get on her next quiz to have an average of 90 for all for quizzes ? Thank you ! (:
Answer by Maths68(1474) (Show Source): You can put this solution on YOUR website!
Let
Elise must score = x

Average = some of quantities / number of quantities
90=(84+96+88+x)/4
90=(268+x)/4
Multiply by 4 both sides
90*4=4*(268+x)/4
360=268+x
360-268=x
92=x
x=92
Elise must score 92 to get an average of 90

Check
=====
Average = some of quantities / number of quantities
Average = (84+96+88+92)/4
Average = 360/4
Average = 90

RELATED QUESTIONS
On her last three quizzes Elise scored 84 96 and 88. What grade must she get on her next... (answered by Maths68)

Beth has the following grades 81%, 88%, 90% 86% on her first four math quizzes. What... (answered by rfer)

Erika has received scores of 82,87,93,95,88, and 90 on math quizzes. What score must... (answered by stanbon)

Tara earned the following quiz scores in her biology class:92,76,80,83 and 91. What must... (answered by dabanfield)

Shauna had an English average of 84%. On her next test she scored 96%, and this raised... (answered by jorel1380)

bethany's average for her first four quizzes is 88. If she wants to have an average of... (answered by ewatrrr)

Kathy has test scores of 88, 90, 91, and 78. What must she score on her next test to have (answered by lynnlo)

After taking 3 math quizzes Elise has an average of 89. What must score on the fourth... (answered by Cromlix)

Lauren has grades of 98 and 86 on her first two chemistry quizzes. What must she score... (answered by josmiceli)