Question

A student has scores of 50%, 90%, 66% and 78% on their exams in class. If the student wants to earn a “D” in the course the average score need to be 60% or above. I’m interval notation, what does their score on the next exam need to be to get at least a 60% average

Answer 1

[10, 100]

Explanation:

The average is the sum of the scores divided by the number of scores.

If x is the score on the next exam, then:

(50 + 96 + 66 + 78 + x) / 5 ≥ 60

(290 + x) / 5 ≥ 60

290 + x ≥ 300

x ≥ 10

The student must score at least 10%. The maximum they can score is 100%, so the interval is [10, 100].