Lesson 7: Ratio and Rate Problem Solving6.AT.3

I can…

I can solve real-world rate problems by finding and using unit rates.

Key words

• Rate — A ratio comparing two amounts with different units, like miles per hour.
• Unit rate — A rate for just 1 of something, like cost for 1 item.
• Per — For each one. Example: 5 dollars per book.
• Problem solving — Using ratios and rates to find a missing amount.
• Proportion — A math sentence saying two ratios are equal. It helps find a missing number.

Steps

1. Team 1 knows that 3 pounds of chicken cost $18.
2. To find the unit rate, I divide the cost by the pounds: 18 divided by 3 = $6 per pound.
3. Now I can find any amount. For 5 pounds, I multiply: 6 x 5 = $30.
4. For 8 pounds, I multiply: 6 x 8 = $48.
5. The unit rate $6 per pound is the shortcut for every amount.

Try it

A printer prints 30 pages in 5 minutes. At this rate, how many pages will it print in 12 minutes?

Check your answer

72

Unit rate: 30 ÷ 5 = 6 pages per minute. In 12 minutes: 6 × 12 = 72 pages.

Sentence starter

I know ___ because ___.

Goal: I can explain my solution using the words rate, unit rate, per, and proportion.