Multiple choice

A is twice as efficient as B and they can together finish a work in 18 days. In how many days can A alone finish the work?

  1. 27

  2. 21

  3. 22

  4. 23

  5. 26
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let B's efficiency be x, then A's efficiency is 2x. Combined efficiency = 3x. Work = 3x * 18 = 54x. A alone takes 54x / 2x = 27 days.

AI explanation

Because A is twice as efficient as B, their efficiency ratio is 2:1, meaning their combined work consists of 3 total parts. Since they finish the work together in 18 days, their combined daily work is 1/18 of the job. A's daily work is 2/3 of their combined work, calculated as 2/3 times 1/18, which equals 1/27. Therefore, A alone can finish the work in 27 days.

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