Digital SAT · Math
Ratios, Rates & Proportions on the Digital SAT: All Question Types
Ratios, Rates, and Proportions covers proportional reasoning and unit work: scaling a ratio, solving a proportion, and converting between units by chaining rates. The dependable method is to set up the relationship so the units cancel, which turns a wordy problem into a single multiplication. This is a Problem-Solving and Data Analysis skill that shows up steadily, and it rewards careful tracking of units more than heavy computation. The common error is inverting a rate or dropping a unit midway, so writing the conversion with units attached keeps it honest. The built-in Desmos calculator handles the arithmetic once the setup is right, so the skill is really about arranging the proportion or the chain of rates correctly.
College Board skill: Problem-Solving and Data Analysis: Ratios, rates, proportional relationships, and units
How Ratios, Rates & Proportions is tested
- how often it appears
- ~1 per test how often it appears
- typical difficulty
- Easy to medium typical difficulty
- practice questions in our bank
- 147 practice questions in our bank
Set up a proportion
Write the ratio with matching units on top and bottom, then cross-multiply. Track units the whole way.
Frequency and difficulty come from this skill's questions across our assembled full-length Digital SAT forms; the practice count is how many drills of these types are in our bank.
2 question types in Ratios, Rates & Proportions
A rate is just two quantities glued together with the word per, like miles per hour or dollars per box.
A ratio compares two amounts; a proportion says two ratios are equal.
Common questions
How do I set up a unit conversion?
Write the starting quantity and multiply by conversion factors arranged so the unwanted units cancel and the target unit remains. Keeping units attached to each number prevents inverting a rate by mistake.
What is the most common mistake on these questions?
Flipping a rate or losing track of a unit partway through. Carrying the units through every step, so they cancel to leave exactly what is asked, catches the error before it reaches the answer.
Do I need Desmos for ratios and rates?
Only for the arithmetic. The real work is arranging the proportion or the chain of rates correctly; once the setup is right, the calculation is quick by hand or in Desmos.
Practice Ratios, Rates & Proportions the way it is tested
Start with the free 16-question diagnostic, then drill any of these types with step-by-step reasoning.