GRE General TestQuantitative ReasoningEasy
A chef is preparing a recipe that calls for 3/4 cup of flour for every 2 servings. If he needs to prepare 10 servings, how many cups of flour will he need?
- A2 1/4 cups
- B4 1/2 cups
- C1 7/8 cups
- D3 3/4 cups
Show answer & explanationAnswer & explanation
Correct answer: D. 3 3/4 cups
The recipe needs 3/4 cup of flour for 2 servings. This means for 1 serving, it needs (3/4) / 2 = 3/8 cup. For 10 servings, it will need 10 * (3/8) = 30/8 = 15/4 = 3 3/4 cups of flour.
Why the other options are wrong
- A. This is incorrect; it might result from 10 * (1/4) + 10 * (1/8).
- B. This is incorrect; it might result from 10 * (3/4) / 1.5.
- C. This is incorrect; it might result from a calculation error such as 10 * (3/16).
Fractional Ratios
Fractional ratios involve comparing quantities where at least one of the quantities is expressed as a fraction, often requiring multiplication or division of fractions.
- Treat fractions like any other number in ratio problems.
- To find a unit rate, divide the fractional quantity by the corresponding whole number.
- Multiply by the target quantity to scale the ratio.
Memory trick: Fractions in recipes scale just like whole numbers, but need fraction math.