Tables and chairs price relation: The cost of 2 tables is equal to the cost of 5 chairs. If the price difference between one table and one chair is Rs 1200, find the cost (price) of one chair.

Introduction / Context:
This unitary-method question uses two linear relations between the price of a table and the price of a chair. By translating the statement “cost of 2 tables equals cost of 5 chairs” and the given price difference into equations, we can determine the price of one chair directly.

Given Data / Assumptions:

• 2 * (price of one table) = 5 * (price of one chair)
• (price of one table) − (price of one chair) = Rs 1200
• All prices are in rupees and refer to identical items.

Concept / Approach:
Let T be the price of a table and C be the price of a chair. From 2T = 5C, we get T = 2.5C. Using the difference T − C = 1200, substitute T = 2.5C and solve for C. This is a straightforward substitution problem leading to one unknown.

Step-by-Step Solution:

Verification / Alternative check:
Compute T: T = 2.5 * 800 = 2000. Check the difference: 2000 − 800 = 1200 (matches). Check the ratio: 2T = 2 * 2000 = 4000 and 5C = 5 * 800 = 4000 (matches).

Why Other Options Are Wrong:

• Rs. 500, Rs. 600, Rs. 700, Rs. 400: None satisfy both 2T = 5C and (T − C) = 1200 when solved consistently.

Common Pitfalls:
Using 2T = 5C as T = 5C/2 and then forgetting to substitute carefully; or mixing up the difference (C − T instead of T − C). Always keep the unknowns labeled clearly to avoid sign errors.

Final Answer:
Rs. 800