An article is sold at a profit of Rs. 30 which is 5% of the cost price if the cost price is increased by 20% and the article is now to be sold at the profit of 15% then find the new selling price?

Let’s denote the cost price of the article as \(C\).

Given that the profit is Rs. 30, which is 5% of the cost price, we have:

\[0.05C = 30\]

Solving for \(C\), we get:

\[C = \frac{30}{0.05} = 600\]

So, the cost price of the article is Rs. 600.

If the cost price is increased by 20%, the new cost price (\(C’\)) will be:

\[C’ = C + 0.20C = 600 + 0.20 \times 600 = 600 + 120 = 720\]

Now, we want to sell the article at a profit of 15% of the new cost price. The selling price (\(S\)) can be calculated as:

\[S = C’ + 0.15C’\]

Substituting the value of \(C’\), we get:

\[S = 720 + 0.15 \times 720 = 720 + 108 = 828\]

Therefore, the new selling price is Rs. 828.