A trader marks the price of a television 30 percent above its cost price and then offers a discount of 10 percent on the marked price. As a result, he earns a profit of Rs. 340 on the sale. What is the cost price of the television set?

Introduction / Context:
This question is a straightforward application of profit and loss along with markup and discount. The trader first increases the price by a certain percentage over cost, then offers a discount, and the net effect is a given profit in rupees. The goal is to recover the cost price from the given profit information.

Given Data / Assumptions:

• Cost price of the television = C (unknown).
• Marked price (MP) = C increased by 30 percent.
• Discount offered on marked price = 10 percent.
• Net profit earned by the trader = Rs. 340.

Concept / Approach:
Markup and discount are applied successively. First the cost price is increased to get the marked price, and then discount is applied to get the selling price. The net profit is selling price minus cost price. By expressing the selling price as a percentage of cost price, we can directly relate profit to cost and solve for the unknown cost price using the given absolute profit in rupees.

Step-by-Step Solution:
Let cost price be C rupees. Marked price = C * (1 + 30 / 100) = 1.30 * C. Discount on marked price = 10 percent, so selling price SP = 1.30 * C * (1 - 10 / 100). Thus SP = 1.30 * C * 0.90 = 1.17 * C. Profit = SP - C = 1.17 * C - C = 0.17 * C. Given profit = Rs. 340, so 0.17 * C = 340. C = 340 / 0.17 = 2000 rupees.

Verification / Alternative check:
Cost price = Rs. 2000. Marked price = 2000 * 1.30 = Rs. 2600. Selling price after 10 percent discount = 2600 * 0.90 = Rs. 2340. Profit = 2340 - 2000 = Rs. 340, which matches the given profit. Therefore cost price is confirmed as Rs. 2000.

Why Other Options Are Wrong:
Rs. 1600, Rs. 2100, Rs. 2200: If you repeat the same markup and discount steps for these cost prices, the resulting profit will not be equal to Rs. 340. They correspond to incorrect manipulation of percentages or arithmetic mistakes.

Common Pitfalls:
Candidates sometimes subtract or add percentages directly without applying them in the correct sequence. Another mistake is to apply the discount on cost price instead of on marked price. Always remember that discount is calculated on marked price, and profit is ultimately based on cost price compared with final selling price.

Final Answer:
The cost price of the television is Rs. 2000.