Shiva purchased 280 kg of Rice at the rate of 15.60/kg and mixed it with 120 kg of rice purchased at the rate of 14.40/kg. He wants to earn a profit of Rs. 10.45 per kg by selling it. What should be the selling price of the mix per kg?

Step 1: Calculate total cost for each type of rice

• 280 kg at Rs. 15.60/kg → Cost = 280 × 15.60 = Rs. 4,368
• 120 kg at Rs. 14.40/kg → Cost = 120 × 14.40 = Rs. 1,728

Step 2: Calculate total quantity and total cost

Total Quantity = 280 + 120 = 400 kg
Total Cost = 4,368 + 1,728 = Rs. 6,096

Step 3: Calculate the cost price per kg of the mixture

Cost Price per kg = 6,096 / 400 = Rs. 15.24

Step 4: Add profit to find selling price

Desired Profit per kg = Rs. 10.45
Selling Price per kg = Cost Price + Profit
                     = 15.24 + 10.45
                     = Rs. 25.69

Answer: Rs. 25.69 per kg

To earn a profit of Rs. 10.45 per kg, Shiva should sell the rice mixture at Rs. 25.69 per kg.

This is a typical question from the profit and loss section of quantitative aptitude. It demonstrates the use of weighted average cost and simple profit addition to calculate the final selling price.