A and B can do a job in 12 days, B and C in 15 days, C and A in 20 days. How long will A take alone to complete the job?
A20 days
B30 days
C40 days
D60 days
Explanation
2(1/A + 1/B + 1/C) = 1/12 + 1/15 + 1/20 = (5 + 4 + 3) / 60 = 12/60 = 1/5 => 1/A + 1/B + 1/C = 1/10. Since 1/B + 1/C = 1/15, 1/A = 1/10 – 1/15 = 1/30. A takes 30 days.
Exam Relevance
- Topic: Work and Time
- Subtopic: Group Work
No Comments