At what proportion should two types of sugar priced at Rs. 18 per kg and Rs. 24 per kg be combined to obtain a blend costing Rs. 20 per kg?

Explanation

To find the correct mixing ratio, use the allegation method: The difference between Rs. 24 and Rs. 20 is 4, and between Rs. 20 and Rs. 18 is 2. Therefore, the ratio is 4:2, which simplifies to 2:1. Hence, the two varieties should be mixed in the ratio 2:1.