Digital SATMath: Problem-Solving and Data AnalysisEasy
A recipe for lemonade calls for 4 lemons for every 6 cups of water. If a large batch requires 15 cups of water, how many lemons are needed?
- A12 lemons
- B8 lemons
- C10 lemons
- D15 lemons
Show answer & explanationAnswer & explanation
Correct answer: C. 10 lemons
The ratio of lemons to water is 4:6. To find the number of lemons for 15 cups of water, set up a proportion: 4/6 = x/15. Solving for x gives 10 lemons.
Why the other options are wrong
- A. Incorrect. This would be the number of lemons if the ratio was 4:5.
- B. Incorrect. This would be the number of lemons for 12 cups of water (4/6 = x/12).
- D. Incorrect. This would imply a 1:1 ratio of lemons to water, which is not given.
Proportional Relationship
A proportional relationship exists between two quantities when their ratio is constant. This means as one quantity changes, the other changes by a constant multiple.
- Can be expressed as a/b = c/d
- Graph is a straight line through the origin
- Constant of proportionality is the ratio y/x
Memory trick: Ratios Remain Equal, Always Balanced.