(! )your class grade consists of 40% homework, 25% quizzes and 35% final exam. suppose you have earned 95% in homework and 84% in quizzes entering the final exam. what percentage do you have to earn in the final in order to have an 87% overall percentage?

Weights:

Homework - .4                                              (score) - (.4)(.95) = .38

Quizzes - .25                                                 (score)  - (.25)(.84) = .21

Final Exam - .35                                             (score) - (.35)(x)

Adding the results up, we get 0.59 + 0.35x

We need to set it up to .87.

0.59 + 0.35x = 0.87

0.59 - 0.59 + 0.35x = 0.87 - 0.59

0.35x = 0.28

x = 0.28/0.35 = .8

Multiplying by 100, he needs an 80% on his final to get an 87% overall

Percentage = dividing by 100.

the desired addition result is 0.87