Question

In a class in which the final course grade depends entirely on the average of four equally weighted 100-point tests, Brad has scored 82, 94, and 92 on the first three. What range of scores on the fourth test will give Brad a B for the semester (an average between 80 and 89, inclusive)? Assume that all test scores have a non-negative value.
Express your answer in interval notation.

Answer 1

Answer:

70 ≤ (94 + 89 + 78 + s)/4 ≤ 79

280 ≤ 261 + s ≤ 316

19 ≤ s ≤ 55

Step-by-step explanation: