Multiple choice

20 boys do one fourth of work in 25 days. How many more boys will be required to complete the remaining work in 50 days?

  1. 8

  2. 10

  3. 15

  4. 20
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

20 boys complete 1/4 of the work in 25 days, so the work rate is (1/4) / (20 × 25) = 1/2000 per boy-day. The remaining 3/4 of the work must be completed in 50 days. Let x be the additional boys needed: (20 + x) × 50 × (1/2000) = 3/4. Solving gives 20 + x = 30, so x = 10 more boys are required.

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