Multiple choice

If A is three times as efficient as B & A can complete a work in $40$ days less time than B. Find in how many days both can complete the work

  1. $15$
  2. $20$
  3. $40$
  4. $50$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A is 3x as efficient as B, so A takes time T, B takes 3T. Given 3T - T = 40, so 2T = 40, T = 20. A takes 20 days, B takes 60 days. Combined rate = 1/20 + 1/60 = 4/60 = 1/15. Both finish in 15 days.

AI explanation

Since A is three times as efficient as B, the ratio of their times taken is 1 to 3, making the difference 2 parts equal to 40 days; therefore, 1 part equals 20 days. A takes 20 days and B takes 60 days, making their combined 1 day work equal to 1/20 plus 1/60, which simplifies to 1/15. Working together, they can complete the work in 15 days.

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