Question

You are studying for your final exam of the semester. up to this point,you recieved 3 exam scores of 76%,99%, and 86%. to recieve a grade of A in the class you must average exam score between 90% and 100% for all 4 exams including the final.
Find the widest range of scores that you can get on the final exam in order to recieve a grade of A for the class.Use interval notation

Answer 1

What you have to do is add up the amount of total grade scores. 76+99+86+x. You get 261+x. you have to get 99% or higher

Answer 2

Answer: The required range of marks is,

[99 100]

Step-by-step explanation:

Let x be the percentage score on the final exam,

Since, 3 exam scores are 76%, 99%, and 86%,

Thus,

$\text{The total average percentage scores in four exams}= \frac{\text{Total sum of four exams percentage}}{4}$

$=\frac{ 76+99+86+x}{4}$

According to the question,

For getting grade A,

90 ≤ The total average percentage scores in four exams ≤ 100

$90\leq \frac{ 76+99+86+x}{4}\leq 100$

$360 \leq 261 + x\leq 400$

$360 - 261 \leq x\leq 400 -261$

$99\leq x\leq 129$

But x can not exceed to 100 %,

$\implies 99\leq x\leq 100$

Thus, the required range of marks in fourth exams for getting grade A is,

[99 100]