Multiple choice

P is thrice as efficient a workman as Q and is able to finish a task in 40 days less than Q. Working together, they will do it in

  1. 30 days

  2. 10 days

  3. 15 days

  4. 19 days

  5. 12 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let Q's time be t. P's time is t/3. t - t/3 = 40, so 2t/3 = 40, t = 60. P takes 20 days, Q takes 60 days. Together: 1/20 + 1/60 = 4/60 = 1/15. They take 15 days.

AI explanation

Since P is thrice as efficient as Q, the ratio of their efficiencies is 3 to 1, meaning their time ratio is 1 to 3. The difference in their times is 2 parts, which equals 40 days, so 1 part equals 20 days. Therefore, P takes 20 days and Q takes 60 days to finish the task. Their combined one day work is 1/20 plus 1/60 equals 4/60 or 1/15, meaning they complete the task together in 15 days.

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