Multiple choice

John works for 5 hours a day for 10 days and completes a piece of work. Bryan works for 8 hours per day for 20 days to complete the same work. Find the ratio of their efficiencies.

  1. 3 : 1

  2. 3 : 2

  3. 2.5 : 1

  4. 3.2 : 1
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D Correct answer
Explanation

John completes the work in 50 hours (5 hours/day * 10 days), and Bryan completes it in 160 hours (8 hours/day * 20 days). Efficiency is inversely proportional to time taken, so the ratio of their efficiencies is 160:50, which simplifies to 3.2:1.

AI explanation

The total work is the product of daily hours and total days, so John's total hours are 5 * 10 = 50 and Bryan's total hours are 8 * 20 = 160. Efficiency is inversely proportional to the time taken to complete the same work. The ratio of their efficiencies is 160 : 50, which simplifies to 3.2 : 1.

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