Let the cost price of the product be Rs \( x \). Gopi marks the price for a 20% profit, making the marked price \( M \):
\( M = x + 0.2x = 1.2x \)
Ravi gets a 10% discount on the marked price, so the selling price \( S \) is:
\( S = M - 0.1M = 0.9M = 0.9 \times 1.2x = 1.08x \)
Ravi saves Rs 15 with this discount, which means:
\( 0.1M = 15 \)
Substitute the value of \( M \):
\( 0.1 \times 1.2x = 15 \)
\( 0.12x = 15 \)
Solve for \( x \) (the cost price):
\( x = \frac{15}{0.12} = 125 \)
The selling price \( S \) is therefore:
\( S = 1.08 \times 125 = 135 \)
Gopi's profit is the difference between the selling price and the cost price:
\( \text{Profit} = S - x = 135 - 125 = 10 \)
Gopi makes a profit of Rs 10 when selling the product to Ravi.