Math 7: Percents and Scales Review

Transcription

1 Name: Class: Date: ID: A Math 7: Percents and Scales Review A scale drawing uses the scale 3 in. = 20 ft. Find the missing measure in. = ft 2. In the scale drawing below, each side is 1.9 cm long. Use the scale factor shown. What is the perimeter of the actual object? 3. Los Angeles is about 385 miles from San Francisco. How far apart would the cities be on a map with a scale of 1 in. = 25 mi? If necessary, round to the nearest hundredth. 4. Two towns that are 31.5 km apart are 3 cm apart on a map. What is the scale of the map? 5. A scale model of a car is 10 in. long. The actual car is 15 ft long. What is the scale of the model? 6. Which of the following would be the most appropriate subject to draw at a scale of 1 : 1? a. a bedroom c. New Jersey b. a micro-organism d. a baseball A map of Utah has a scale of 1 cm : 30 mi. 7. The border of Utah and Wyoming measures about 3.7 cm. How long is the actual border of Utah and Wyoming? Round the answer to the nearest ten miles. 8. You have a family portrait that is 4 inches high by 6 inches wide. You want to enlarge the photo so that it is 30 inches wide with dimensions proportional to those of the original.. a. Write and solve a proportion to find the height of the enlarged photo. b. The photo lab charges $.02 per square inch to print enlarged photos. What is the area in square inches of your enlarged photo? How much will it cost to buy three prints? 9. Find 70% of Liam wants to buy a bicycle that costs $ His parents say Liam must raise 40% of the money himself. How much money must Liam raise? 11. Use mental math to find 90% of $

2 Name: ID: A 12. A ski club planned a trip to Lake Tahoe, and 44 of the members signed up to go. If this is 30% of the club, how many members does the ski club have in total? 13. a. Utopia has a population of 17,000. If 70% of the population voted in the last presidential election, how many people voted in the election? b. The number of voters last year was 40% of the number of voters in the previous year. How many people voted in the previous year? Use a proportion to solve. If necessary, round to the nearest percent. 14. What percent of 44 is 11? 15. There are 12 players on the basketball roster. 9 of the players are in the 8th grade. What percent of the team is not in the 8th grade? is 20% of what number? 17. A used appliance store estimates that the value of an oven-range combination decreases by about 10% in the first year of use. If the original price of a one-year-old oven-range combination was $1,100, what is the value of the oven-range now? 18. On a factory floor, 30 out of every 140 toy robots is defective. What percent of the toy robots are defective? Round your answer to the nearest hundredth. 19. A new law requires that 15% of an individual s income to be invested in the stock market. Your accounts show that you need to put $435 in the stock market this year. How much did you earn this year? 20. a. A certain tennis racquet at Bob s Tennis Racquet Emporium costs $ with a sales tax of 7%. What is the total cost of the racquet? b. Tennis Pro, a store across the street, offers a before-tax price of 10% less than Bob s store for a similar racquet. What will the price tag be on the similar racquet at Tennis Pro? Use an equation to solve % of what number is 47? 22. What number is 25% of 770? 23. What percent of 355 is 71? 24. Find the total cost of a $ airline ticket with a sales tax of 4%. 25. The bill is $ Find the amount of a 15% tip. 26. Suppose you rent a limousine for a formal reception. The bill for the evening is $ A tax of 6% will be added, and you want to tip the chauffeur 20% for excellent driving. How much will you pay in total? 2

3 Name: ID: A 27. Find the percent of increase. Round to the nearest tenth. 125 to Find the percent of markup. Round to the nearest tenth. $33.00 to $ Find the percent of discount. Round to the nearest tenth. original price $24,365; selling price $16, A department store purchases a dress for $80. To sell the dress to customers, the price is marked up by 19%. You hand the clerk $110. How much change will you get back? 31. Suppose you have a coupon for 10% off and you use it to buy a CD which was already discounted 15%. Do you end up a discount of 25%? Explain your answer. 3

4 ID: A Math 7: Percents and Scales Review Answer Section m in cm = 21 km 5. 1 in. : 18 in. 6. D mi 8. [4] a. h = the height of the enlarged photo 4 6 = h 30 6h = 4 30 h = h = 20 in. b. Area of the enlarged photo = 600 in. 2 Cost for three prints = 3 area of photo $.02/in. 2 = = $36.00 [3] correct answer for (a) and correct process for (b) with minor error [2] minor error in (a) with (b) calculated correctly based on incorrect value [1] minor error in (a) with (b) calculated incorrectly or missing $ $ ,900 people; 29,750 people % $ % 19. $ $192.60; $ % 24. $ $ $ % % 1

5 ID: A % 30. $ Answer may vary. Sample: No; with the first discount you pay or 85% of the original price. The coupon gives you a 10% discount so you pay the remaining 90%. The double-discount price is 90% of 85% of the original price or (0.90)(0.85) = (0.765). The discount is = or 23.5%. 2