An intern can a job in 15 days . The manager and senior manager are busy with…
2025
An intern can a job in 15 days . The manager and senior manager are busy with other priorities and thus take 25 and 40 days respectively to complete the task. How long will they task to finish the task if all of them work together?
- A.
7
- B.
722/29
- C.
7.59
- D.
821/29
Attempted by 28 students.
Show answer & explanation
Correct answer: C
Work rates: Intern = 1/15 per day, Manager = 1/25 per day, Senior manager = 1/40 per day.
Convert to a common denominator (LCM of 15, 25, 40 is 600): 1/15 = 40/600, 1/25 = 24/600, 1/40 = 15/600.
Add the rates: 40/600 + 24/600 + 15/600 = 79/600 per day.
Time to finish = reciprocal of the combined rate = 600/79 days ≈ 7.5949 days (≈ 7.59 days).
Final answer: 600/79 days, which is approximately 7.59 days.