Question

Elizabeth hopes to get at least a 90 average on her science tests. She has one more test before the end of the school year. Her past test scores are 79,
94, 91, and 92. Write and solve an inequality the represents this situation. Explain to her how she can determine what the lowest score she can earn on her final test and still reach her goal.

Answer 1

(79 + 94 + 91 + 92 + x) / 5 > = 90 (thats greater then or equal)
(356 + x) / 5 > = 90....multiply both sides by 5, eliminating the 5 on the left 
356 + x > = 90 * 5
356 + x > = 450
x > = 450 - 356
x > = 94......lowest score she can earn is 94