If prime cost is Rs. 20,000; factory overheads are 25% of prime cost and office overheads are 80% of factory overheads then the office cost would be

Rs. 25,000
Rs. 29,000
Rs. 36,000
Rs. 45,000

The correct answer is: C. Rs. 36,000

Factory overheads = 25% of prime cost = 25/100 * 20,000 = Rs. 5000
Office overheads = 80% of factory overheads = 80/100 * 5000 = Rs. 4000
Therefore, the office cost is Rs. 4000.

Option A is incorrect because it is the total prime cost.
Option B is incorrect because it is the total factory overheads.
Option D is incorrect because it is the total prime cost plus the factory overheads.