88599 Prabhat wants to invest the total amount of ₹ 15,000 in saving certificates and national saving bonds. According to rules, he has to invest at least ₹\(2000\) in saving certificates and \(₹ 2500\) in national saving bonds. The interest rate is \(8 \%\) on saving certificate and \(10 \%\) on national saving bonds per annum. He invest \(₹ x\) in saving certificate and \(₹ y\) in national saving bonds. Then the objective function for this problem is