Question

In Ms. Miller's English class, students are given five tests in a semester. At the end of the semester, the scores that a student has earned on the five tests are averaged to obtain that student's class average. So far, DeShawn has taken the first four tests, and his scores are 71%, 90%, 82%, and 77%. Which of the following is the range of all the class averages that DeShawn could possibly receive at the end of the semester?

Answer 1

The options are;

A. 64 - 84%

B. 64 - 100%

C. 80 - 84%

D. 80 - 100%

Answer:

Option A: 64% - 84%

Explanation:

We are told his scores on the five tests are averaged to obtain that student's class average.

Now, we are only given 4 of the scores which are; 71%, 90%, 82%, and 77%.

Now, maximum value of the 5th score will be 100% while the minimum value of the 5th score will be 0%

Thus,to find the range of the average score, we will find the average with the maximum 5th score and the minimum 5th score.

With maximum 5th score of 100%, we have an average of;

(71% + 90% + 82% + 77% + 100%)/5 = 420%/5 = 84%

With minimum 5th score of 0%, we have an average of;

(71% + 90% + 82% + 77% + 0%)/5 = 320%/5 = 64%

Thus, the range of all the class averages is; 64% - 84%