WBCS.LIVE practice question

A can complete a task in 20 days, and B can complete the same task in 30 days. If they work together, how many days will they take to finish it?

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. 10 days
  2. 15 days
  3. 12 days
  4. 18 days

Correct answer and explanation

Correct answer: 12 days

Explanation: āœ… Correct Answer: C) 12 days šŸ“š Explanation: Person A's one-day work output is exactly 1/20 of the task, and B's one-day work output is exactly 1/30. Working perfectly together, their combined one-day work is 1/20 + 1/30. Making the denominators equal (LCM is 60) gives 3/60 + 2/60 = 5/60, which mathematically simplifies to 1/12. Therefore, together they will finish the entire task in exactly 12 days.