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ASVAB · Ratios, Proportions, and Rates

If 5 pounds of apples cost $4, how much would 15 pounds of apples cost?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

$12

  1. A $8
  2. B $14
  3. C $12
  4. D $10

Why this is the answer

Set up a proportion: 5 pounds / $4 = 15 pounds / x. Cross-multiply: 5x = 60. Divide: x = $12. Alternative thinking: 15 pounds is 3 times 5 pounds, so the cost is also 3 times: 3 × $4 = $12. Either method works. Proportions are central to many ASVAB problems: cooking (recipe scaling), maps (distance scale), construction (mixing ratios), and any 'if X equals Y, then how much for Z' situation. Set up as fraction equal to fraction with corresponding units in the same position. Cross-multiply to solve: (a/b) = (c/d) means ad = bc. The unit-rate method also works: $4 ÷ 5 pounds = $0.80 per pound; $0.80 × 15 pounds = $12. Use whichever method clicks for the problem. Verify the answer is reasonable — 15 pounds should cost roughly three times 5 pounds.
Source: ASVAB AR — Direct Proportion

Practice more questions

This question is from our ASVAB Practice Tests practice test. Take the full practice test to test your knowledge across all Ratios, Proportions, and Rates and other topics.

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About this topic: Ratios, Proportions, and Rates

Ratios, proportions and rates cover scale drawings, recipes, speed and unit prices. Almost every question reduces to setting two ratios equal and cross-multiplying — once you see that pattern the section becomes fast. This is one of 11 Arithmetic Reasoning questions on ratios, proportions, and rates, each with a full explanation on a single study page.

New to this exam? Our ASVAB exam guide explains the format, scoring, and how to prepare.

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