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SAT Math skill page

SAT Ratios and Proportions Practice

Use ratios, unit rates, and proportions to solve SAT word problems without losing track of the parts.

10-16 min practice time3 questions on pageProblem Solving and Data Analysis
Practice time10-16 min
Question bank3 questions
Best forProblem Solving and Data Analysis

What this tests

What to know for this SAT skill

Dolphin question bank

Practice your skill

Question 1 of 3Medium
Anita created a batch of green paint by mixing 2 ounces of blue paint with 3 ounces of yellow paint. She must mix a second batch using the same ratio of blue and yellow paint as the first batch. If she uses 5 ounces of blue paint for the second batch, how much yellow paint should Anita use?
  1. Exactly 5 ounces
  2. 3 ounces more than the amount of yellow paint used in the first batch
  3. 1.5 times the amount of yellow paint used in the first batch
  4. 1.5 times the amount of blue paint used in the second batch
Show answer and solution
Correct answerD. 1.5 times the amount of blue paint used in the second batch

Solution walkthrough

  1. It's given that Anita used a ratio of 2 ounces of blue paint to 3 ounces of yellow paint for the first batch. For any batch of paint that uses the same ratio, the amount of yellow paint used will be , or 1.5, times the amount of blue paint used in the batch.
  2. Therefore, the amount of yellow paint Anita will use in the second batch will be 1.5 times the amount of blue paint used in the second batch. Alternate approach: It's given that Anita used a ratio of 2 ounces of blue paint to 3 ounces of yellow paint for the first batch and that she will use 5 ounces of blue paint for the second batch.
  3. A proportion can be set up to solve for , the amount of yellow paint she will use for the second batch: . Multiplying both sides of this equation by 3 yields , and multiplying both sides of this equation by yields .
  4. Dividing both sides of this equation by 2 yields . Since Anita will use 7.5 ounces of yellow paint for the second batch, this is times the amount of blue paint (5 ounces) used in the second batch.
Why the other choices miss
Choices A, B, and C are incorrect and may result from incorrectly interpreting the ratio of blue paint to yellow paint used.
Question 2 of 3Medium
The ratio 140 to m is equivalent to the ratio 4 to 28. What is the value of m?
  1. 140
  2. 280
  3. 560
  4. 980
Show answer and solution
Correct answerD. 980

Solution walkthrough

  1. The correct answer is . It's given that the ratio to is equivalent to the ratio to .
  2. Therefore, the value of can be found by solving the equation . Multiplying each side of this equation by yields .
  3. Multiplying each side of this equation by yields . Dividing each side of this equation by yields .
  4. Therefore, the value of is .
Question 3 of 3Easy
Shaquan has 7 red cards and 28 blue cards. What is the ratio of red cards to blue cards that Shaquan has?
  1. 1 to 4
  2. 4 to 1
  3. 1 to 7
  4. 7 to 1
Show answer and solution
Correct answerA. 1 to 4

Solution walkthrough

  1. It's given that Shaquan has 7 red cards and 28 blue cards.
  2. Therefore, the ratio of red cards to blue cards that Shaquan has is 7 to 28.
  3. This ratio can be reduced by dividing both parts of the ratio by 7, which yields the ratio 1 to 4.
Why the other choices miss
Choice B is incorrect. This is the ratio of blue cards to red cards that Shaquan has. Choice C is incorrect and may result from a calculation error when reducing the ratio. Choice D is incorrect. This may result from finding the ratio of blue cards to red cards, or 28 to 7, and then making a calculation error when reducing the ratio.

Avoid these traps

Common mistakes on this skill

Using one part as the whole

In a ratio like 3:5, the whole is 8 parts, not 5 parts.

Mixing part-to-part and part-to-whole

Read whether the question asks for one group, another group, or the total.

Scaling only one quantity

When a proportion changes, every related quantity must scale by the same factor.

Study plan

How to practice this skill in Dolphin

  1. Add ratio parts when the question asks for the total.
  2. Find the value of one part before finding a specific group.
  3. Use tables to keep proportional quantities aligned.
  4. Check whether your answer is a part, a total, or a rate.
Practice ratios and proportions in Dolphin

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FAQ

Questions about SAT Ratios and Proportions Practice

What is the difference between a ratio and a proportion?

A ratio compares quantities. A proportion says two ratios are equal and lets you scale from one situation to another.

Why do ratios show up so much on the SAT?

Ratios connect to rates, scale drawings, mixtures, data tables, and many real-world word problems.

What is the most common ratio mistake?

Students often treat one side of the ratio as the whole instead of adding all parts to find the total.