Correct Answer: Rs. 8500

Solution : Let the cost price of the manufacturer be Rs. $x$.
Hence, profit of manufacturer = 18% of his cost price = Rs.$\frac{18x}{100}$
The selling price of manufacturer = cost price of wholesaler = Rs. $\frac{118x}{100}$
Profit of wholesaler = 20% of his cost price = $\frac{20}{100}\times \frac{118x}{100}=\frac{236x}{1000}$
The selling price of the wholesaler = Cost price of the retailer
= $\frac{118x}{100}+\frac{236x}{1000}=\frac{1416x}{1000}$
Profit after 25% profit of retailer = $\frac{25}{100}\times \frac{1416x}{1000}=\frac{354x}{1000}$
Selling price of retailer = Cost price of customer = $\frac{1416x}{1000}+\frac{354x}{1000}=\frac{177x}{100}$
⇒ $15045=\frac{177x}{100}$
⇒ $x=8500$
Hence, the correct answer is Rs. 8500.