Question

A mixture of 12 kg of wheat flour costing Rs. 16 per kg and 4 kg of corn flour costing Rs. 2 per kg is sold at Rs. 16 per kg. What is the profit made in selling 40 kg of the mixture?

• A. Rs. 140
• B. Rs. 280
• C. Rs. 300
• D. Rs. 420

Hint:

Find the weighted average cost price per kg of the mixture, subtract it from the selling price to get profit per kg, then multiply by 40.

Answer 1

The Correct Option is A

Instead of finding a per kg profit, we can scale the original 16 kg batch up to 40 kg directly, keeping the wheat to corn ratio fixed at 12:4, that is 3:1.

1. Scale the batch: 40 kg of mixture in a 3:1 ratio means wheat flour = \( \dfrac{3}{4} \times 40 = 30\) kg and corn flour = \( \dfrac{1}{4} \times 40 = 10\) kg.
2. Find the cost of this scaled batch: Cost = 30(16) + 10(2) = 480 + 20 = Rs. 500.
3. Find the revenue from selling it: Revenue = 40 kg x Rs. 16/kg = Rs. 640.

Profit = Revenue - Cost = 640 - 500 = Rs. 140, which matches the per kg method exactly and confirms option A.