Answer:
The earning would be approximately 79.29 % in the final exam
Explanation:
Given,
In class grade the percentage of homework = 40 % = 0.40 ,
Percentage of quizzes = 25 % = 0.25,
Percentage of final exam = 35 %=0.35,
Also, there is an earning of 95% in homework and 84% in quizzes entering the final exam,
⇒ Earning in homework = 95 % of 0.40,
And, earning in quizzes = 84 % of 0.25
Let x be the percentage do you have to earn in the final in order to have an 87% overall percentage,
![\implies 95 \%\text{ of }0.40+84\%\text{ of }0.25 + x\%\text{ of }0.35=87\%](https://img.qammunity.org/2019/formulas/mathematics/middle-school/y6qc8c90pqeg61n7sqpnzpf6ny83bqkpop.png)
![59.25+0.35x=87](https://img.qammunity.org/2019/formulas/mathematics/middle-school/jhprei32xm22judvt4ty2f144ncdtxk4ec.png)
![0.35x=27.75](https://img.qammunity.org/2019/formulas/mathematics/middle-school/kdlwpsvxvquf7073gqd6j7tzwsz7i8rn7c.png)
![\implies x = 79.2857142857\approx 79.29\%](https://img.qammunity.org/2019/formulas/mathematics/middle-school/g4hsgkno41hm49ywar7h4zhxf3o17gslgs.png)
Hence, the earning would be approximately 79.29 % in the final exam in order to have an 87% overall percentage.