12 chairs and 6 tables were bought for Rs. 12,600. If the average cost of a table is Rs. 1,500, then find the average cost of a chair.

Correct option is D

Given:
Number of chairs = 12
Number of tables = 6
Total cost = Rs. 12,600
Average cost of one table = Rs. 1,500
Formula Used:
Total cost = Cost of tables + Cost of chairs
​$$\text{Average cost} = \frac{\text{Total cost}}{\text{Number of items}}$$​​
Solution:
Total cost of tables = 6 × 1500 = Rs. 9000
Total cost of chairs = 12,600 − 9,000 = Rs. 3,600
Average cost of one chair = $$\frac{3,600 }{ 12}$$​ = Rs. 300 
Exam Hall Method: