A grocer purchased 25.6 kg of sugar at Rs. 12.50 per kg and mixed it with 12 kg sugar at Rs. 15 per kg. At what rate should he sell the mixture to gain 12.8 %? 1. Rs. 17 per kg 2. Rs. 15.0 per kg 3. Rs. 16.5 per kg 4. Rs. 16 per kg None of these 5.