Suppose you ve earned a 92% and 90%, respectively, on your first two tests this quarter. What range of scores could you earn on your third test in order to have a test average between 90% and 93%? Write your answer as a compound inequality.

Question

Suppose you ve earned a 92% and 90%, respectively, on your first two tests this quarter.  What range of scores could you earn on your third test in order to have a test average between 90% and 93%?  Write your answer as a compound inequality.

anonymous · Answer

Let x be the grade on your final test.
so you want your test average between 90 and 93%, so this calls for an inequality
90< average < 93
and the average is the average of the three tests (1/3)(92+90+x)
substitute the average expression in and solve for x