Multiple choice

A can do a piece of work in 24 days, while B can do it in 16 days. With the help of C, they finish the work in 8 days. C alone can do the work in

  1. 32 days

  2. 36 days

  3. 40 days

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

A's rate = 1/24, B's rate = 1/16. (A+B+C)'s rate = 1/8. C's rate = 1/8 - (1/24 + 1/16) = 1/8 - (2/48 + 3/48) = 6/48 - 5/48 = 1/48. C takes 48 days.

AI explanation

Using the LCM method, let the total work be 48 units. A's efficiency is 2 units per day and B's efficiency is 3 units per day. Together, A and B have an efficiency of 5 units per day. With the help of C, their combined efficiency becomes 6 units per day (48 units divided by 8 days). This means C's efficiency is 1 unit per day (6 minus 5). Therefore, C alone can do the 48 units of work in 48 days.

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