A, B and C can finish a piece of work in 12 days, 15 days and 20 days respectively. If 1st day A+B, 2nd day B+C, 3rd day C+A work and they work in the same manner, then in how many days the work will be finished ?
Answer & explanation
Correct answer: option 4
1st day work ( A + B ) = 9R
2nd day work ( B + C ) = 7R
3rd day work ( C + A ) = 8R
total 3 days work = 24R
6 days work = 48R
7th day ( A + B ) will work i.e. 9R
remaining work = 60R - 57R = 3R
on next day ( B + C ) will work with 7R efficiency
time = \(\frac{3R}{7R}\) = \(\frac{3}{7}\)
total days taken = 7 + \(\frac{3}{7}\) = 7\(\frac{3}{7}\) days