A can do one - third of a work in 9 days, whereas B can do 25% of the same work in same no. of days. Both work together for 12 days. C completes the remaining work in 4 days. Find the time taken by B and C together to complete the work.
Answer & explanation
Correct answer: option 3
Time taken by A to complete one - third of the work = 9 days
Time taken by A to complete 100% of the work = 27 days
Time taken by B to complete 25% of the work = 9 days
Time taken by B to complete 100% of the work = 36 days
Total work = 108
Work completed in 12 days = Efficiency x No. of days
= (3 + 4) x 12 = 7 x 12 = 84
Work left = 108 - 74 = 24
Efficiency of C = \(\frac{Work}{Time\; taken}\) = \(\frac{24}{4}\) = 6
Efficiency of B and C = 3 + 6 = 9
Time taken by B and C to complete the work = \(\frac{Total\; work}{Efficiency}\)
= \(\frac{108}{9}\) = 12 days