3.5 · Part II
Second Practice Form · Independent Application and Spiral Review
Compare Ratios · Unit rate
- Convert each ratio to a unit rate (e.g. price per item or miles per gallon)
- Alternatively, scale both ratios to a common term (like a common denominator)
- Compare the resulting unit rates to identify the better buy or faster rate
- Compare Ratios (Comparar razones) — Decide which ratio is greater, less, or equal by using equivalent ratios or unit rates.
- Unit rate (Tasa unitaria) — A rate for just 1 of something, like cost for 1 item.
- Equivalent ratio (Razón equivalente) — Two ratios that mean the same thing.
- Compare (Comparar) — To look at ratios and see which is bigger, smaller, or equal.
- Simplify (Simplificar) — To write a ratio with smaller numbers that still compares the same way. 6:8 and 3:4 are the same ratio.
- Common denominator (Denominador común) — A bottom number that two fractions can share so you can compare them.
- A common mistake in Compare Ratios is thinking the ratio with the bigger raw number automatically wins — like assuming Chef Tran's 8 tablespoons of cocoa must be more chocolatey than Chef Reyes's 6 tablespoons, without checking that the milk amounts (14 oz vs. 10 oz) are different. Never compare the raw numbers alone — always scale both ratios to the same amount or find each unit rate first.
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1 MULTIPLE CHOICE
Car A travels 180 miles on 6 gallons. Car B travels 225 miles on 9 gallons. Which car gets better gas mileage?
- ACar A, at 30 miles per gallon
- BCar B, at 25 miles per gallon
- CCar B, because it traveled farther
- DThey are equal
✏️ Workspace & Solution Steps -
2 MULTIPLE CHOICE
Chef A uses 2 cups of cheese for every 8 crackers. Chef B uses 3 cups of cheese for every 9 crackers. Who uses more cheese per cracker?
- AChef B
- BChef A
- CThey use the same amount
- DCannot determine
✏️ Workspace & Solution Steps -
3 MULTIPLE CHOICE
Which ratio is greater: 3:4 or 5:8?
- A3:4
- B5:8
- CThey are equal
- DCannot determine
✏️ Workspace & Solution Steps -
4 MULTIPLE CHOICE
Which lemonade recipe is more lemony? Recipe A: 2 lemons for 6 cups of water. Recipe B: 3 lemons for 7 cups of water.
- ARecipe B
- BRecipe A
- CThey are the same
- DCannot determine
✏️ Workspace & Solution Steps
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5 OPEN RESPONSE
Store A sells 5 notebooks for $12. Store B sells 8 notebooks for $20. Without calculating, a student says Store B must be cheaper because you get more notebooks. Is the student's reasoning valid? Find the unit rates to prove your answer.
✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.