Multiple choice

A is twice as good a work man as B and together they finish the work in 14 days. In how many days A alone can finish the work?

  1. 23

  2. 22

  3. 20

  4. 21
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A = 2B. Combined rate = A + B = 3B. 3B = 1/14 of work per day. B = 1/42. A = 2B = 2/42 = 1/21. A alone takes 21 days.

AI explanation

Using the efficiency method, since A is twice as good a workman as B, the ratio of their daily work is 2 to 1. Let A's daily work be 2 units and B's daily work be 1 unit, making their combined daily output 3 units. Working together at 3 units per day, they finish the work in 14 days, meaning the total work is 3 times 14, which equals 42 units. Dividing the total 42 units by A's daily rate of 2 units gives 21 days for A to finish the work alone.

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