Digital SATMath: Problem-Solving and Data AnalysisEasy
A biologist is studying a local pond ecosystem. She observes that the ratio of frogs to fish in the pond is 3:5. If there are 120 frogs in the pond, how many fish are there?
- A72
- B360
- C200
- D600
Show answer & explanationAnswer & explanation
Correct answer: C. 200
To find the number of fish, set up a proportion using the given ratio and the number of frogs. If 3 parts represent 120 frogs, then 1 part represents 40. Therefore, 5 parts (fish) would be 5 * 40 = 200.
Why the other options are wrong
- A. This would be the number of frogs if the ratio was 5:3 and there were 120 fish.
- B. This incorrectly multiplies the number of frogs by the fish ratio part (5) without considering the frog ratio part (3).
- D. This incorrectly multiplies the number of frogs by the sum of the ratio parts (3+5=8).
Ratio Application
Ratios express the relative size of two or more values. They can be used to find unknown quantities when one quantity and the ratio are known.
- Ratios can be written as a:b, a/b, or 'a to b'.
- To solve for an unknown, set up a proportion.
- Ensure units and corresponding parts of the ratio are consistent.
Memory trick: Ratios Relate Amounts, Find the Missing Piece.