Ramesh is twice as good a workman as Sunil and finishes a piece of work in 3 hours less than Sunil. In how many hours they together could finish the same piece of work ?

Let Sunil finishes the job in $\mathrm{x}$ hours.

Then, Ramesh will finish the job in $\frac{x}{2}$ hours.

We have,

$$\begin{gathered} x-\frac{x}{2}=3 \\ \Rightarrow x=6 \end{gathered}$$

Therefore, Sunil finishes the job in 6 hours and Ramesh in $3$ hours.

Work done by both of them in 1 hour

$$\begin{gathered} =\frac{1}{6}+\frac{1}{3} \\ =\frac{1}{2} \end{gathered}$$

They together finish the piece of work in $2$ hours.