Ramesh marks an article at Rs. 6000. After allowing a discount of 20% to the customer, he still earns a profit of 60%. What is the cost price of the article in rupees?

Introduction / Context:
This question connects marked price, discount, selling price and cost price in a profit and loss situation. We are told the marked price and discount offered, plus the profit percentage on cost price. From this, we must work backwards to find the cost price. This type of question is typical in shopkeeper and trader profit problems.

Given Data / Assumptions:
- Marked price (MP) of the article = Rs. 6000.
- Discount given = 20 percent on the marked price.
- Profit earned = 60 percent of cost price.
- We must determine the cost price (CP) of the article.

Concept / Approach:
The selling price (SP) is found from marked price and discount. Profit is calculated using SP and CP. Since we know the required profit percentage on CP, we can relate SP and CP using the formula:
SP = CP * (1 + profit percent / 100). We first compute SP from the discount, then equate it to CP * 1.60 and solve for CP.

Step-by-Step Solution:
Marked price MP = Rs. 6000. Discount = 20%, so discount factor = 1 - 20 / 100 = 0.80. Selling price SP = MP * 0.80 = 6000 * 0.80 = Rs. 4800. Profit percentage = 60%, so SP = CP * (1 + 60 / 100) = CP * 1.60. Therefore, CP * 1.60 = 4800. So CP = 4800 / 1.60. Compute CP = 3000.

Verification / Alternative check:
Check the result: If CP is 3000 and profit is 60%, then SP should be 3000 * 1.60 = 4800. This matches the SP we computed from discount on the marked price (6000 * 0.80 = 4800). Therefore, both approaches agree, confirming that the cost price must be Rs. 3000.

Why Other Options Are Wrong:
3600, 4200 and 4800: These values do not satisfy both conditions simultaneously when used as CP. They lead to incorrect profit percentages or wrong selling prices when rechecked.
3500: This value would result in a profit different from exactly 60%, so it does not match the given information.

Common Pitfalls:
Some learners mistakenly treat the 60 percent profit as being calculated on the marked price or selling price instead of cost price. Others may directly subtract the discount from the marked price and treat that result as cost price, ignoring the profit information. Always remember that profit percentage is defined with respect to cost price, while discount percentage is defined with respect to marked price.

Final Answer:
The cost price of the article is Rs. 3000.