Find unit rates · lesson · Graymalkin Lane

How much for one

💡 To find a unit rate, divide so that the second amount becomes 1.

A rate compares two different kinds of things, like miles and hours. A unit rate is the amount for just one of the second thing.

The word "per" means "for each". Miles per hour means miles for each one hour.

To find it, divide the first amount by the second amount.

🧠 Let's work it out

A bus goes 216 miles in 4 hours. How many miles per hour?

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💡 A unit price is the cost of one item or one ounce: total cost divided by how many.

Stores sell things in packs. To find the price of one, divide the total cost by the number of items.

Money answers often have cents. A price can be less than one dollar, like 0.65.

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5 pens cost $3.25. What does one pen cost?

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💡 To compare two deals, turn both into unit rates first, then compare the unit rates.

Two packs with different sizes are hard to compare. Find the price of one unit for each pack.

The lower price per unit is the better buy.

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Bag A: 4 pounds for $6.20. Bag B: 6 pounds for $8.70. Which is the lower price per pound?

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💡 Decide which amount the question wants per one, and once you have a unit rate you can multiply or divide to reach any amount.

Read the question to see what it wants "per" what. Minutes per mile is time divided by miles. Miles per minute is the other way.

Once you know the rate for one, you can scale. Multiply to go up. Divide to see how many units you need.

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Lee walks 5 miles in 55 minutes. How many minutes for 7 miles?

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💡 A rate with fractions works the same way: divide the first amount by the second.

Sometimes both amounts are fractions, like half a mile in a quarter hour. You still divide to find the amount for one.

Dividing by a fraction is the same as multiplying by its flip.

🧠 Let's work it out

A turtle walks 3/4 of a mile in 1/2 of an hour. What is its speed in miles per hour?

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