Find unit rates like miles per hour and cost per item, then use them to make better-buy decisions.
A rate compares two quantities with different units. A unit rate tells you the amount for exactly 1 of one quantity — found by dividing.
Better-buy comparisons: Find the unit price for each option. The smaller unit price is the better deal.
Store B's unit price ($1.50) is lower, so it's the better buy even though the total is higher.
1. A cyclist rides 45 miles in 3 hours. What is the unit rate in miles per hour?
Unit rate = total miles ÷ total hours = 45 ÷ 3 = 15 miles per hour.
2. A store sells 5 notebooks for $10.00. What is the cost per notebook (in dollars)?
Cost per notebook = $10.00 ÷ 5 = $2.00 each.
3. A car drives 180 miles in 3 hours. What is the unit rate in miles per hour?
180 ÷ 3 = 60 miles per hour.
4. A pack of 8 juice boxes costs $4.00. What is the cost per juice box (in dollars)?
$4.00 ÷ 8 = $0.50 per juice box.
5. Store X: 6 apples for $3.00. Store Y: 9 apples for $3.60. Which store has the better unit price?
Store X: $3.00 ÷ 6 = $0.50 each. Store Y: $3.60 ÷ 9 = $0.40 each. $0.40 < $0.50, so Store Y is cheaper per apple.
6. A printer prints 56 pages in 8 minutes. How many pages does it print per minute?
56 ÷ 8 = 7 pages per minute.
7. Brand A: 4 granola bars for $2.00. Brand B: 6 granola bars for $2.40. Which brand is the better buy?
Brand A: $2.00 ÷ 4 = $0.50 each. Brand B: $2.40 ÷ 6 = $0.40 each. Brand B is cheaper per bar.