To construct a wall, sand and cement are mixed in the ratio of 3 : 1. The cost of sand and that of cement are in the ratio of 1 : 2. If the total cost of sand and cement to construct the wall is 1000 rupees, then what is the cost (in rupees) of cement used? A. 400 B. 600 C. 800 D. 200

GATE 2023 · General Aptitude · Alligation Mixture · medium

Answer: A. Cost of cement = Rs 400.

1. Assign unit costs: The cost ratio 1:2 means cement is twice as expensive per unit.
2. Compute expenditure on each: Multiply quantity (from mixing ratio 3:1) by unit cost for each ingredient.
3. Find k from total cost: Total expenditure = 1000.
4. Calculate cost of cement: Cement expenditure = 2k = Rs 400.