Ralph needs to earn a B in his Geology class. His current test scores are

82,83, 90, and 77. His final exam is worth
4 test scores. In order to earn a B​,
Ralph's average must lie between
80 and 89 inclusive. What range of scores can Ralph receive on the final exam to earn a
B in the​ course?

3 answers

80 ≥ (4t + 82 + 83 + 90 + 77) / 8 ≥ 89
it works better if you use <=
oops...

89 ≥ (4t + 82 + 83 + 90 + 77) / 8 ≥ 80