## Elementary Algebra

She must get a score of 96 or higher on the fifth exam. The solution set is {x|x $\geq$ 96}
Let x represent the score on the fifth exam. Her average = $\frac{ 86+88+89+91+x }{5}$ Because her average needs to be 90 or higher, we solve the following inequality. Average $\geq$ 90 $\frac{ 86+88+89+91+x }{5}$ $\geq$ 90 Multiply both sides by 5. 86+88+89+91+x $\geq$ 450 354 + x $\geq$ 450 x $\geq$ 96 She must get a score of 96 or higher on the fifth exam. The solution set is {x|x $\geq$ 96}