Question

A and b can finish a work in 20 days a alone can do 1/5th of work in 12 days. In how many days can b alone do it?

Answer 1

Please see the attachment

Answer 2

B alone can do work in 30 days.

Step-by-step explanation:

Let B alone can do work in x days.

Given:

• A and B can finish a work in 20 days.
• A alone can do 1/5th of work in 12 days.

$\rightarrow \: \frac{1}{A} = \frac{1}{5} \times ( \frac{1}{12} ) \\ \rightarrow \: \frac{1}{A} = \frac{1}{60} \\ \rightarrow \: \frac{1}{20} = \frac{1}{A} + \frac{1}{B} \\ \rightarrow \: \frac{1}{20} = \frac{1}{60} + \frac{1}{x} \\ \rightarrow \: \frac{1}{x} = \frac{1}{20} - \frac{1}{60} \\ \rightarrow \: \frac{1}{x} = \frac{2}{60} \\ \rightarrow \: x = 30 \: days$

So, B alone can do work in 30 days.