Elementary Algebra

Published by Cengage Learning
ISBN 10: 1285194055
ISBN 13: 978-1-28519-405-9

Chapter 4 - Proportions, Percents, and Solving Inequalities - Chapter 4 Review Problem Set: 75

Answer

She must receive a score of 89 or higher on the exam. The solution set is {x|x $\geq$ 89}.

Work Step by Step

Let x represent the score on the fifth exam. Her average is $\frac{83+89+78+86+x}{5}$. Because her average should be 85 or higher, we solve the following inequality. Average $\geq$ 85 $\frac{83+89+78+86+x}{5}$ $\geq$ 85 Multiply both sides by 5. 83+89+78+86+x $\geq$ 425 336 + x $\geq$ 425 x $\geq$ 89 She must receive a score of 89 or higher on the exam. The solution set is {x|x $\geq$ 89}.
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