Percent Applications Lesson 3.5 A mark-up is an increase from the amount of money a store pays for an item (wholesale price) to the amount it sells the item for (retail price). To find the percent of mark-up on an item, find the percent of increase. A discount is the decrease in the price of an item after it goes on sale. To find the percent of discount on an item, find the percent of decrease. Example 1 Solution A pawn shop owner buys a ring for $75 and sells it at an 80% mark-up. Find how much the ring sold for. Use proportions, the percent equation or percent of increase to find the mark-up. The mark-up is the part. The original amount is the whole. Proportions Percent Equation Percent of Change 80 Mark-up Mark-up 100 = x 75 Original Amount x = 80% 75 0.8 = x 75 Original Amount Use cross products. 100x = 6000 Divide by 100. x = 60 The mark-up is $60. Convert to a decimal. x = 0.8 75 Simplify. x = 60 The mark-up is $60. Multiply by 75. 75 0.8 = x 75 75 60 = x The mark-up is $60. The mark-up is $60. The owner sold the ring for $75 + $60 = $135. The ring sold for $135. Example 2 Solution Sesily found an outfit that is 20% off of the original price of $68. Find the discounted price of the outfit. The discount is the part. The original amount is the whole. Proportions Percent Equation Percent of Change 20 Discount x = 20% 68 Discount 100 = x 68 Original Amount 0.2 = x 68 Original Amount Convert to a decimal. x = 0.2 68 Multiply by 68. Use cross products. 100x = 1360 Divide by 100. x = 13.6 Simplify. x = 13.6 68 0.2 = x 68 68 13.6 = x The discount is $13.60. The discount is $13.60. The discount is $13.60. The discount is $13.60. The new price for the outfit is $68 $13.60 = $54.40. The outfit costs $54.40 on sale. Lesson 3.5 ~ Percent Applications 97
In 2012, Alaska, Delaware, Montana, New Hampshire and Oregon did not have a sales tax. The remaining forty-five states in the United States have sales taxes. A sales tax is a tax placed on items sold at stores in the state. The taxes are considered as revenue for the state government. The tax is a mark-up applied to an item above the price listed on the price tag. Most states do not tax food. Sometimes counties and cities have additional sales taxes on items to raise money for county or city budget expenditures. Example 3 Solutions In 2012 Leah bought a new stereo in Seattle, Washington for $250. Find the actual amount she paid at the checkout counter if she was charged: a. the state sales tax of 6.5%. b. the city and state tax combined of 9.5%. a. Find 6.5% of $250. Use the percent equation. x = 0.065 250 x = 16.25 Leah paid an additional $16.25. Add both amounts for the total. $250 + $16.25 = $266.25 Leah would pay $266.25 for the stereo, including sales tax. b. Find 9.5% of $250. Use the percent equation. x = 0.095 250 x = 23.75 Leah paid an additional $23.75. Add both amounts for the total. $250 + $23.75 = $273.75 Leah would pay $273.75 with the city and state taxes combined. Example 4 Solution Roy paid $8.05 for an antique model truck. It was on sale for 30% off. Find the original price of the model truck. Let x be the original price of the model. Since the model was 30% off, Roy paid 70% of the original price. This means 70% of the original price is $8.05. Write a proportion. 70 100 = 8.05 x Use cross products to solve. 70x = 805 x = 11.5 The antique model truck was originally $11.50. 98 Lesson 3.5 ~ Percent Applications
exercises Find the amount of each mark-up or discount. 1. original price: $25.00 2. original price: $340.00 percent of mark-up: 15% percent of mark-up: 5% 3. original price: $145 4. original price: $62.00 percent of mark-up: 30% percent of discount: 20% Find each selling price. 5. original price: $10.00 6. original price: $100.00 percent of mark-up: 40% percent of mark-up: 125% 7. original price: $24.50 8. original price: $48.00 percent of mark-up: 12% percent of discount: 15% 9. original price: $18.50 10. original price: $245.00 percent of discount: 20% percent of discount: 25% Show all work necessary to justify your answer for each Exercise. 11. Tirzah was selling artwork at a local farmer s market. Near the end of the day she decided to sell her items at a 15% discount. How much did she sell her painting for if the original price was $300.00? 12. Sasha owns a clothing store. She bought jeans for $15.00 each and plans to sell them. She hopes to make a 20% profit on the sales of the jeans. What price should she put on each pair of jeans? 13. Veronica went shopping at a store when everything in the store was 30% off. She bought a shirt that was originally $18.00 and a matching sweater that was originally $45.00. How much did Veronica pay for the items after the discount? 14. Tricia bought a hat for Griffin s birthday. She paid $12.00 for the hat because she found it on sale for 70% off the original price. What was the original price of the hat? 15. Your bill for a meal at a restaurant is $32.00. You plan to leave a 15% tip. What will be the total cost of your meal, including tip? 16. Trevor and Zane went to a restaurant for lunch. The bill was $22.00. Trevor paid for lunch and left a 15% tip. How much did he pay altogether? Lesson 3.5 ~ Percent Applications 99
Use the table of sales taxes to complete Exercises 17-20. 17. Oscar bought a computer for $750.00. How much would he pay including the state sales tax rate in: a. California? b. Washington? c. New York? 18. Conrad bought a car for $20,000. How much would he pay including the state sales tax rate in: a. Los Angeles, California? b. Dallas, Texas? c. Chicago, Illinois? State State Sales Tax in 2012 Large City Sales Tax in 2012 California 7.25% Los Angeles 8.75% Florida 6.0% Miami 7.0% Illinois 6.25% Chicago 9.5% New York 4.0% New York City 8.375% Oregon 0.0% Portland 0.0% Texas 6.25% Dallas 8.25% Washington 6.5% Seattle 9.5% 19. Matt visited his friends in New York City, New York. He bought a souvenir T-shirt at the ball park. The T-shirt cost $35 before the New York City sales tax was applied. How much did the T-shirt cost after taxes were added? 20. Many stores in the state of Washington allow Oregonians to buy items without sales tax. If an Oregonian went to Washington to buy a new van for $45,000, how much would he save in sales tax compared to a Washington resident? Use the Washington state sales tax in your answer. Show all work necessary to justify your answer for each Exercise. 21. Your bill for a meal at a restaurant is $45.00. A 6% sales tax will be added to the bill. You leave a 15% tip. What is the total cost of your meal? 22. A laptop computer is originally priced at $1,800 and is on sale for 10% off. After continuing to not sell, the computer goes on sale for 15% off the sale price. What is the new sale price of the computer? 23. A shoe store in Oregon is selling a pair of basketball shoes for $145.00. The shoes are $160 at a store in Washington, but they are on sale there for 15% off the original price. A sales tax of 6.5% will be added to the sale price. a. Find the price of the shoes in Washington. b. Is it cheaper to buy the shoes in Oregon or Washington? 24. Henry and Theo started a business selling DVDs. They purchase each DVD for $10. Henry says they should mark-up each DVD by 60% and sell them at a 20% discount. Theo insists it is better to mark-up each DVD by 20% and sell them at a 60% discount. a. Find the price of each DVD using Henry s method. b. They will sell the same number of DVDs whether they sell them at Henry s price or Theo s price. Which person s price will give them the most money? Use mathematics to justify your answer. 100 Lesson 3.5 ~ Percent Applications
review 25. Lori used 7 gallons of gas to travel 147 miles. At this rate, how many gallons of gas will she use to drive 315 miles? 26. Mario ran 8 miles in 2_ hour. At this rate, how long will it take him to run 12 miles? 3 27. A skateboarder rides at a speed of 10 miles per hour. a. How many feet does she ride in one hour? b. How many feet does she ride in one minute? 28. Ruby blinks 22 times per minute. How many times do her eyes blink in one week? 29. Use the similar figures to the right. a. Find their scale factor. b. Find the ratio of their areas. c. The area of the smaller pentagon is 3 square inches. What is the area of the larger pentagon? 3_ 5 inches 4_ 5 inches Tic-Tac-Toe ~ Com m ission Commission is the amount of money a sales person makes after a sale to a customer. Suppose a store clerk earns a 20% commission on all items sold and he sells $250 worth of merchandise one day. That clerk will make $50 in commission. Commission = Amount of sales Rate of commission C = 250 0.2 C = 50 1. The seventh grade class sold coupon books for a fundraiser. The class earned 30% commission on their total sales. If the class sold $2,450 worth of coupon books, how much money did they earn? 2. A real estate agent works on a commission of 5 1_ 2 %. If she sells a house for $189,000, how much will she earn in commission? 3. Sandra earns $300 per week plus 6% commission on all sales made at an electronics store. If she sold $4,000 worth of electronics last week, how much money did she earn all together for the week? 4. Larry earns $650 per week plus 4% commission on all sales made. Last week he earned a total of $910. How much did Larry sell last week? 5. Niki earns $225 per week plus 8% commission on all sales over $1,000 each week. Last week she sold $2,300 worth of merchandise. How much did she earn all together for the week? 6. Farma earns $150 plus 15% on all sales over $2,000 each week. Last week he earned a total of $525. How much did Farma sell last week? Lesson 3.5 ~ Percent Applications 101
Tic-Tac-Toe ~ Si m ple I n te r e st When money is borrowed over a length of time, interest is often charged. When money is saved in a bank, interest is often earned. Suppose you borrow $300 to buy a bike at 5% interest over 2 years. To find the amount of interest you will pay you can use a simple interest formula: Formula Problem I = Interest I =? P = Principal (the original amount of money borrowed or saved) P = $300 R = Rate of interest written as a decimal R = 5% but rewrite this as 0.05 for the formula T = Time (written in years) T = 2 years I = PRT I = (300)(0.05)(2) = 30 You will pay $30 interest in addition to the $300 owed for a total of $330. 1. Colleen borrowed $1000 to buy a new computer at 8% interest over 4 years. How much money did she have to pay back for the loan? 2. Jeff put $450 in the bank. His account earns 2% interest per year. How much interest did Jeff have in the bank after one year if he did not make any other deposits? 3. Jin borrowed $220 to buy a new video game system at 9% interest over 3 years. How much money did Jin really pay for the new video game system, including interest? 4. Kay borrowed $700 for a new camera at a rate of interest over 5 years. She cannot remember the rate of interest but knows she paid $910 to repay the loan. What was her rate of interest as a percent on the money borrowed? 5. You borrow $500 for a new tablet at 5% interest. You can pay the loan back after 2 years or after 5 years. How much more money will you owe if you choose 5 years instead of 2 years? Tic-Tac-Toe ~ Com munit y Data Research and find at least 10 facts or rates in your community that you can compare from last year to this year. Some examples might include amount of rainfall, number of students passing the state test, number of students on the track team or number of policemen at the local station. Find the percent increase or decrease for each quantity or rate from last year to this year. Record whether it is a percent increase or a percent decrease. Organize the information in a chart to include the quantities or rates from last year as well as this year, the percent increase or decrease and whether or not it was an increase or a decrease. Finally, predict what will happen next year if the percent change remains the same. Include this in the chart. 102 Lesson 3.5 ~ Percent Applications