A and B together can complete a piece of work in 15 days. B and C together can do it in 24 days. If A is twice as good a workman as C. Then in how many days can B alone complete the work?

Answer: Option B

Solution

Answer: Option B

Solution:

$$\begin{array}{rl}& \text{Let the efficiency of C}=\text{x and A}=\text{2x}\\ & \text{A}+\text{B}=\text{8}\\ & \text{B}+\text{C}=\text{5}\\ & \overline{\text{A}-\text{C}=3}\\ & 2\text{x}-\text{x}=3\\ & \text{x}=3\\ & \text{Efficiency of A}=\text{6, B}=\text{2, C}=\text{3}\\ & \text{Required answer}\\ & \text{B}=\frac{120}{2}=60\text{ days}\end{array}$$