The cost price of 15 kg wheat is equal to the selling price of 10 kg wheat, the cost price of 18 kg rice is equal to the selling price of 15 kg rice and the cost price of 15 kg maize is equal to the selling price of 20 kg maize. If the ratio of the cost price of wheat, rice, and maize is 4 : 5 : 6 respectively then find the overall profit/loss percentage on selling 1 kg wheat, 2 kg rice, and 1 kg maize.