Six tables and twelve chairs are bought for Rs 7,800. If the average cost of a table is Rs 750, what is the average cost of a chair?

Correct option is A

Given:

Six tables and twelve chairs are bought for Rs 7,800.

If the average cost of a table is Rs 750.

Formula used:

$$\text{Average} = \frac{\text{Sum of all observations}}{\text{Number of observations}}$$​

Solution:

The average cost of one table is Rs. 750,

The total cost of six tables = 6 × 750 = 4500

The total cost of tables and chairs is Rs. 7,800.

The total cost of twelve chairs = 7800 − 4500

The total cost of twelve chairs = 3300

​The average cost of one chair = $$\frac{3300}{12} = 275$$

So, the average cost of a chair is Rs. 275.

Thus, the correct answer is (a).