Question

Working together, A and B can complete a piece of work in 12 days, B and C can complete the same piece of work in
15 days. If A is as twice efficient as C, then the time taken by B alone to complete the same piece of work is:​

Answer 1

Answer:

B and C together can do it in 15 days. A is twice as good a workman as C. From (1) and (2) substitute the values of 1/a and 1/c. Therefore, B alone can do it in 20 days.