c0b90e0aa51cbdae40108746fbf0f91e.ppt

- Количество слайдов: 13

5 -2 Ratios, Rates, and Unit Rates 5 -2 Rates, and Unit Rates Warm Up Problem of the Day Lesson Presentation Course 3 3

5 -2 Ratios, Rates, and Unit Rates Vocabulary rate unit price Course 3

5 -2 Ratios, Rates, and Unit Rates A rate is a comparison of two quantities that have different units. Ratio: 90 3 Rate: 90 miles 3 hours Course 3 Read as “ 90 miles per 3 hours. ”

5 -2 Ratios, Rates, and Unit Rates Unit rates are rates in which the second quantity is 1. The ratio 90 can be simplified by dividing: 3 90 = 30 3 1 unit rate: 30 miles, or 30 mi/h 1 hour Course 3

5 -2 Ratios, Rates, and Unit Rates Additional Example 1: Finding Unit Rates Fred can type 30 words in half a minute. How many words can he type in 1 minute? 30 words 1 2 minute Write a rate. 30 words • 2 = 60 words 1 1 minute 2 minute • 2 Multiply to find words per minute. Fred can type 60 words in one minute. Course 3

5 -2 Ratios, Rates, and Unit Rates Check It Out: Example 1 Penelope can type 90 words in 2 minutes. How many words can she type in 1 minute? 90 words 2 minutes Write a rate. 90 words ÷ 2 = 45 words 2 minutes ÷ 2 1 minute Divide to find words per minute. Penelope can type 45 words in one minute. Course 3

5 -2 Ratios, Rates, and Unit Rates Unit price is a unit rate used to compare price per item. Course 3

5 -2 Ratios, Rates, and Unit Rates Additional Example 4 A: Finding Unit Prices to Compare Costs Pens can be purchased in a 5 -pack for $1. 95 or a 15 -pack for $6. 20. Which is the better buy? price for package = $1. 95 $0. 39 Divide the price by the number of pens 5 of pens. price for package = $6. 20 $0. 41 number of pens 15 The better buy is the 5 -pack for $1. 95. Course 3

5 -2 Ratios, Rates, and Unit Rates Additional Example 4 B: Finding Unit Prices to Compare Costs Jamie can buy a 15 -oz jar of peanut butter for $2. 19 or a 20 -oz jar for $2. 78. Which is the better buy? price for jar = $2. 19 $0. 15 number of ounces 15 Divide the price by the number of ounces. price for jar = $2. 78 $0. 14 number of ounces 20 The better buy is the 20 -oz jar for $2. 78. Course 3

5 -2 Ratios, Rates, and Unit Rates Check It Out: Example 4 A Golf balls can be purchased in a 3 -pack for $4. 95 or a 12 -pack for $18. 95. Which is the better buy? price for package = $4. 95 $1. 65 Divide the price by the number of balls 3 of balls. price for package = $18. 95 $1. 58 number of balls 12 The better buy is the 12 -pack for $18. 95. Course 3

5 -2 Ratios, Rates, and Unit Rates Check It Out: Example 4 B John can buy a 24 oz bottle of ketchup for $2. 19 or a 36 oz bottle for $3. 79. Which is the better buy? price for bottle = $2. 19 $0. 09 number of ounces 24 Divide the price by the number of ounces. price for bottles = $3. 79 $0. 11 number of ounces 36 The better buy is the 24 -oz jar for $2. 19. Course 3

5 -2 Ratios, Rates, and Unit Rates Try These! 1. Jacob can buy a 32 oz bottle of BBQ sauce for $2. 93 or a 36 oz bottle for $3. 19. Which is the better buy? 2. John can buy a 8 pencils for $1. 25 or a 12 pencils for $2. 00. Which is the better buy? 3. Mary made $25. 00 for working 7 hours at the mall. How much did Mary make per hour? 4. Lisa paid $158. 00 for 3 pair of jeans. What did Lisa pay for each pair of jeans? 5. Bob typed 593 words in 4 minutes. How many words did Bob type per minute? Course 3

5 -2 Ratios, Rates, and Unit Rates Try These! Round to nearest hundredth 1. $2. 93 / 32 = $0. 09 (better buy) $3. 19 / 36 = $11. 6 2. $1. 25 / 8 = $0. 16 (better buy) $2. 00 / 12 = $0. 17 3. $25. 00 / 7 hours = $3. 57 / Hr 4. $158. 00 / 3 pair of jeans = $52. 67 / jean 5. 593 / 4 minutes = 148. 3 words/minute Course 3