Computing Grades In your Economics 101 class, you have scores of 68, 82, 87, and 89 on the...

Computing Grades In your Economics 101 class, you have scores of 68, 82, 87, and 89 on the first four of five tests. To get a grade of B, the average of the first five test scores must be greater than or equal to 80 and less than 90.

(a) Solve an inequality to find the range of the score that you need on the last test to get a B.

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(b) What score do you need if the fifth test counts double?