A can plough a field in 12 hrs and B can do it in 4 hrs. Together with C, they completed the work in 2 hrs. Then, how long does C alone take to do the job?
Answer & explanation
Correct answer: option 1
Let total work = 12,
Efficiency of A + B + C = \(\frac{Total\; work}{No.\; of \;hrs}\)
=- \(\frac{12}{2}\) = 6
Efficiency of C = eff(A + B + C) - eff(A) - eff(B) = 6 - 3 - 1 = 2
Time taken by C alone = \(\frac{Total\; work}{Efficiency}\)
= \(\frac{12}{2}\) =6 hrs