Rates and Unit Rates Course 3 Vocabulary rate
Rates, and Unit Rates Course 3
Vocabulary rate unit price
A rate is a comparison of two quantities that have different units. Ratio: 90 3 Rate: 90 miles 3 hours Read as “ 90 miles per 3 hours. ”
Unit rates are rates in which the second quantity (or the denominator) 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
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.
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.
Unit price is a unit rate used to compare price per item.
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.
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.
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.
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.
Using Rate Tables to Find Values Rate tables can be used to answer questions. Three sweaters cost $18. What is the cost of 7 sweaters? Number Cost 3 18
Ratio Tables Three sweaters cost $18. What is the cost of 7 sweaters? Number 1 Cost 6 3 18
Ratio Tables Three sweaters cost $18. What is the cost of 7 sweaters? Number 1 Cost 6 3 18 7 42
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?
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
Homework Page Page 51, 52, 53, 55, 56, #1 # 5, 7, 8 #10 a/c (don’t do “b” and “d” #12 -14 #24
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