A can do a piece of work in 20 days and B in 30 days. They work together for 8 days and then both leave the work. Then C alone finishes the remaining work in 5 days. In how many days will C finish the full work?
Answer & explanation
Correct answer: option 2
A : B
Days 20 : 30
Efficiency 3 : 2
Say, the total work = 60
Work done A + B in 8 days = Efficiency x No. Of Days = (3 + 2) x 8 = 5 x 8 = 40
Remaining work = 60 - 40 = 20
This work is completed by C in 5 days,
Thus efficiency of C = \(\frac{Work}{Days}\)
= \(\frac{20}{5}\) = 4
Time taken By C alone to complete this work = \(\frac{Total\; work}{Efficiency}\)
= \(\frac{60}{4}\) = 15 days