Warm-up
Three quick questions from earlier lessons.
Discover
4 tickets cost 20 dollars. Which describes the price?
- 5 dollars per ticket
- 0.2 dollars per ticket
Key idea
A unit rate is the amount for one.
A unit rate tells how much for one unit: dollars per pound, miles per hour. Every ratio gives two unit rates, and ; choose the one the question asks for. Compare prices or speeds with unit rates.
Worked example
150 miles in 3 hours.
50 miles per hour
150 ÷ 3.
In 5 hours: miles
Use the rate.
Your turn, guided
Your turn: 6 pens cost 9 dollars. Dollars per pen.
9 ÷ 6.
Practice ★
- 4 pounds of apples cost 20 dollars. What is the price per pound (dollars)?
- 3 pounds of apples cost 27 dollars. What is the price per pound (dollars)?
- A car travels 175 miles in 5 hours at a constant speed. How far does it go in 9 hours?
Watch out!
Practice ★★
- Store A sells 2 notebooks for 8 dollars. Store B sells 11 for 66 dollars. What is the lower price per notebook (dollars)?
- Store A sells 6 notebooks for 24 dollars. Store B sells 10 for 90 dollars. What is the lower price per notebook (dollars)?
- Boss problem. Mia runs 5 km in 30 minutes at a steady pace.
Exit ticket
Three questions to check you have got it.
- 4 pounds of apples cost 20 dollars. What is the price per pound (dollars)?
- 3 pounds of apples cost 27 dollars. What is the price per pound (dollars)?
- 8 pounds of apples cost 72 dollars. What is the price per pound (dollars)?
Summary card
Unit rates
Amount for one: divide by the number of units.
Watch out: which quantity is per what?