Multiple choice

A works twice as fast as B. If both of them can finish a piece of work together in 12 days, in how many days will B do it alone?

  1. 24 days

  2. 27 days

  3. 36 days

  4. 48 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let B's rate be x, then A's rate is 2x. Combined rate is 3x = 1/12. So x = 1/36. B takes 36 days to finish alone.

AI explanation

Using the efficiency ratio method, let the work done by B in one day be 1 unit, meaning A does 2 units per day. Their combined daily work is 3 units, and since they finish the job in 12 days, the total work is 36 units. To find the time B takes to complete the job alone, divide the total work by his daily capacity of 1 unit. The result is 36 days.

Keep practicing — related questions