Problem
You earn \( \$ 13 \) per hour plus a commission equal to \( x \) percent of your sales as a cell phone sales representative. What is your commission percentage \( (x) \) if you work 8 hours with sales of \( \$ 1200 \) worth of merchandise and your total earnings for the day is \( \$ 140 \) ?
Solution
Step 1 ：\( ext{Total Earnings} = \text{Hourly Earnings} + \text{Commission} \)
Step 2 ：\( 140 = 13 \times 8 + 1200x \)
Step 3 ：\( x = 0.05 \)
