Multiple choice

Dev completed the school project in 20 days. How many days will Arun take tocomplete the same work if he is 25% more efficient than Dev?

  1. 10 days

  2. 12 days

  3. 16 days

  4. 15 days

  5. 5 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Efficiency ratio (Arun:Dev) = 1.25 : 1 = 5 : 4. Time ratio is inverse of efficiency ratio = 4 : 5. Dev takes 20 days (5 parts). 1 part = 4 days. Arun takes 4 parts = 16 days.

AI explanation

If Arun is 25% more efficient than Dev, the ratio of their efficiencies is 125 to 100, or 5 to 4. Because time taken is inversely proportional to efficiency, the ratio of time taken by Dev to Arun is 5 to 4. Let Arun's time be x; then 20 / x = 5 / 4, which gives x = 16 days.

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