1. A racing bike that was originally $2,500 was on sale at 20% off. If the bike was sold for $1,800 after a second discount, what was the second percent of discount? COURSE 2 LESSON 6-9 The bike originally cost $2,500 and was discounted by 20%. Given that the final cost of the bike was $1,800, your goal is to find the second discount. First, find the price after the first discount. As a result of the 20% discount, the cost was 80% of the original price. 0.80 $2,500 = $2,000 The cost of the bike after the first discount was $2,000. Subtracting $1,800 from $2,000 gives you $200, the amount of the second discount. 6-9 Write an Equation

2. (continued) COURSE 2 LESSON 6-9 2,000d = 200 The second discount was 10%. = Divide each side by 2,000. d = 0.1 Simplify. 2,000d 2,000 200 2,000 = 10% Change to percent. 6-9 Write an Equation WordsPercent of second discount of $2,000 is $200. Equation d2,000=200 Let d = the percent of second discount.

3. (continued) COURSE 2 LESSON 6-9 To check, confirm that the second discount of 10% does give the final price of $1,800. Ten percent of $2,000 is $200 and $2,000 – $200 is $1,800. So the answer checks. 6-9 Write an Equation

4. A stereo originally costs a storeowner $94.99. The percent of markup is 45%. What is the maximum percent of discount the store can offer and make a profit of at least $15? COURSE 2 LESSON 6-9 First, find the price that the store sells the stereo. $94.99 + 0.45 94.99 = $137.74 The store sells the stereo for $137.74. To make at least $15 on the stereo, the store will have to sell it for at least $94.99 + $15, or $109.99. So the discount will be $137.74 – $109.99, or $27.75. The stereo costs the storeowner $94.99. The percent of markup is 45%. Your goal is to find the maximum percent of discount the store can give and still make $15 in profit. 6-9 Write an Equation

5. (continued) COURSE 2 LESSON 6-9 The maximum percent of discount the store can offer is 20%. 137.74d 137.74 27.75 137.74 = Divide each side by 137.74. d = 0.2015 Use a calculator. d 20% Change decimal to percent. 6-9 Write an Equation WordsMaximum percent of discount of $137.74 is $27.75. Equation d $137.74 = $27.75 137.74d = 27.75 Let d = the maximum percent of discount.

6. (continued) COURSE 2 LESSON 6-9 You can try, check, and revise different percents. The price of the stereo has to be at least $109.99 for the store to earn $15. Percent Percent Paid Discountby CustomerCost of StereoResult 19%81%81% $137.74 = 111.57 20%80%80% $137.74 = 110.19 21%79%79% $137.74 = $108.81Too low 22%78%78% $137.74 = $107.44Too low The answer checks. 6-9 Write an Equation

7. COURSE 2 LESSON 6-9 A department store pays $20 for each watch in a shipment. The store sells the watches for $75. What is the maximum percent of discount the store can offer and make a profit of at least $20 on each watch? 47% 6-9 Write an Equation