A can paint a house in 18 days and B can do it in 12 days. Together with C, they completed the work in 4 days. Then, how long does C alone take to do the job?
Answer & explanation
Correct answer: option 4
Let total work = 36,
Efficiency of A + B + C = \(\frac{Total\; work}{No.\; of \;days}\)
=- \(\frac{36}{4}\) = 9
Efficiency of C = eff(A + B + C) - eff(A) - eff(B) = 9 - 2 - 3 = 4
Time taken by C alone = \(\frac{Total\; work}{Efficiency}\)
= \(\frac{36}{4}\) = 9 days