Question

medal to whoever answers

jack has gotten an average of 78, 85 and 93 on his first three tests. after he takes his fourth test, he wants his average to be between 83 and 87, inclusive. set up and solve a compound inequality to find out what jack needs to score on his test to reach his goal.

Answer 1

(78 + 85 + 93 + x)/4 > 83
(256 + x)/4 > 83
256 + x > 332
x > 332 - 256
x > 76

(78 + 85 + 93 + x)/4 < 87
(256 + x)/4 < 87
256 + x < 348
x < 348 - 256
x < 92

76 < x < 92