Percent-to-ratio conversion: Thirty-five percent of one number equals twice seventy-five percent of another number. Find the ratio of the first number to the second number.
Correct Answer: 30 : 7
Introduction / Context:Translating percentage statements into algebraic equations enables quick ratio determination. This question asks you to equate percent portions of two unknown numbers and express the result as a clean integer ratio.
Given Data / Assumptions:
- Let the first number be x and the second be y.
- 35% of x equals twice 75% of y.
Concept / Approach:Convert percentages to decimals and set up the equation. Then isolate x/y to get a ratio. Multiply numerator and denominator to clear decimals and express the ratio with integers in lowest terms.
Step-by-Step Solution:0.35x = 2 * 0.75y ⇒ 0.35x = 1.5y.x / y = 1.5 / 0.35.1.5 / 0.35 = 150 / 35 = 30 / 7.Therefore, the required ratio is 30 : 7.
Verification / Alternative check:Pick y = 7 (for convenience). Then x = 30 satisfies 0.35 * 30 = 10.5 and 2 * 0.75 * 7 = 10.5, verifying the equality precisely.
Why Other Options Are Wrong:
- 35 : 6, 23 : 7, and 32 : 9 do not satisfy 0.35x = 1.5y when tested.
Common Pitfalls:
- Mishandling percent-to-decimal conversion (e.g., mixing 35 with 0.35).
- Forgetting to simplify the final ratio to lowest integer terms.
Final Answer:30 : 7