A man sold an article at a gain of $5\%$. Had he sold it for $\text{Rs. }240$ more, he would have gained $8\%$ . Find the cost price of the article.

Let the cost price of the article be $\text{CP}$.
Initial Selling Price $({\text{SP}}_1)=105\%\text{ of CP}$
New Selling Price $({\text{SP}}_2)=108\%\text{ of CP}$

The difference between the two selling prices is given as $\text{Rs. }240$:

$${\text{SP}}_2-{\text{SP}}_1=240$$

$$(108\%-105\%)\text{ of CP}=240$$

$$3\%\text{ of CP}=240$$

$$\frac{3}{100}\times \text{CP}=240$$

$$\text{CP}=\frac{240\times 100}{3}=8000$$

Therefore, the cost price of the article is $\text{Rs. }8000$.