A, B, and C are capable of completing a job in 30, 45, and 90 days,…
2025
A, B, and C are capable of completing a job in 30, 45, and 90 days, respectively. A works every day, while
B and C join A every fifth day. How long will it take to finish the task?
- A.
25 days
- B.
18 days
- C.
16 days
- D.
12 days
Attempted by 4 students.
Show answer & explanation
Correct answer: A
In four ordinary days A completes 4/30 = 2/15 of the job. On every fifth day A, B and C together complete 1/30 + 1/45 + 1/90 = 1/15. Thus each 5-day cycle completes 1/5 of the job, so the task takes 25 days.