Explanation:

- Sushma's purchase: 6 tables and 12 chairs for Rs 12,000.

- Sold tables at a 15% profit.

- Sold chairs at a 10% loss.

- Total profit from sales: Rs 300.

- Goal: Find the total cost of the tables.

Let's break it down:

1. Total Cost of tables + chairs = Rs 12,000.

2. Let the cost of tables be Rs 'x'.

3. So, the cost of chairs would be Rs (12,000 - x).

4. Profit from tables = 15% of x = 0.15x.

5. Loss from chairs = 10% of (12,000 - x) = 0.1(12,000 - x).

6. Total profit = Profit from tables - Loss from chairs.

7. 0.15x - 0.1(12,000 - x) = 300.

Let's solve:

0.15x - 1200 + 0.1x = 300,

=> 0.25x - 1200 = 300,

=> 0.25x = 1500,

=> x = 6000.

- Total cost of the tables is Rs 6,000.

Option 2 is correct: Rs 6,000