A profit of 20% is earned by selling an article for Rs.2,400. If the same article were sold for Rs.2,600, then the gain percentage would be:

Correct option is C

Given:
Selling Price= Rs.2,400
Profit = 20%
Again, same article selling price =Rs. 2,600
Formula Used:
​$$\text{Gain Percentage} = \left( \frac{\text{Gain}}{\text{Cost Price}} \right) \times 100$$​​
Solution:
Cost Price = $$\frac{\text{Selling Price}}{1 + \frac{\text{Profit Percentage}}{100}}$$​​
Cost Price = $$\frac{2400}{1 + \frac{20}{100}}$$​ = Rs. 2000
New Selling Price = Rs. 2600
New Profit = New Selling Price - Cost Price = 2600 - 2000 = Rs. 600
$$\text{Gain Percentage} = \left( \frac{\text{Gain}}{\text{Cost Price}} \right) \times 100$$ = $$\left( \frac{600}{2000} \right) \times 100$$​ = 30%