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ASVAB · Ratios, Proportions, and Rates

If 5 workers can complete a job in 8 days, how many days would 10 workers take to complete the same job?

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

4

  1. A 16
  2. B 2
  3. C 6
  4. D 4

Why this is the answer

Inverse proportion: 5 workers × 8 days = 10 workers × d days. d = 40 ÷ 10 = 4 days. This is an inverse (indirect) proportion: more workers means fewer days, so the product workers × days stays constant (40 worker-days). Doubling the crew halves the time. The distractor 16 days is the direct-proportion trap (doubling workers and doubling days), which would make a bigger crew slower — a sign the relationship was set up backwards.
Source: ASVAB AR, Inverse Proportion

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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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