Question

A works twice as fast as B. They work together and complete a job in 8 days. How long would A take to complete the job?

Answer 1

$\text{Ratio of Rate of working of A \& B = 2:1}$

$\text{Ratio of time taken is = 1:2}$

$\text{Let x day taken by A}\text{.}$

$\text{So,;2 day taken to work}{\left(\frac{1}{x}\right)}^{th}$

$\text{and 2x day by B}$

$\text{1 day}\to {\left(\frac{1}{2x}\right)}^{th}$

$\text{1 day}\to \frac{1}{x}+\frac{1}{2x}=\frac{3}{2x}$

$\text{8 day}\to \frac{8\times 3}{2x}$

$\frac{8\times 3}{2x}=1$

$x=12\text{day}$