Question

The average of Katelyn's three test scores must be at least 95 to earn an A in the class. Katelyn scored 91 on the first test and 95 on the second test. What scores can she get on her third test to guarantee an A in the class.

Write your answer in interval notation

Answer 1

Explanation:

Assuming the test scores are based on a 100 pt max and they are weighted equally:

Find the average of the three scores

(95 + 91 + x) / 3 >= 95 Multiply both sides by '3'

95 + 91 + x >= 285 subtract 95 and 91 from both sides

x >= 99

so she has to score a 99 or 100 on the test :

Interval notation:

99 <= x <=100 or [99,100}