A shopkeeper who sells same marked price shirts, announced an offer – if one buys two shirts then the buyer can buy the third shirt at the discounted price of Rs. 150. Ram took the offer and bought 12 shirts by paying Rs. 5,000 only. Find the overall discount percentage allowed by the shopkeeper.

Sure, let's solve the problem step by step.

Step 1: Let's assume the marked price of each shirt is Rs. X.

Step 2: According to the offer, if Ram buys two shirts, he can buy the third shirt at a discounted price of Rs. 150. So, the total cost of 3 shirts will be 2X + 150.

Step 3: Ram bought a total of 12 shirts, so the cost of 12 shirts will be (2X + 150) * 4.

Step 4: Ram paid Rs. 5,000 for the 12 shirts. So, we can set up the equation (2X + 150) * 4 = 5000.

Step 5: Simplifying the equation, we get 8X + 600 = 5000.

Step 6: Solving for X, we subtract 600 from both sides: 8X = 4400.

Step 7: Dividing both sides by 8, we get X = 550.

Step 8: Now, we know that the marked price of each shirt is Rs. 550.

Step 9: To find the overall discount percentage, we need to calculate the total discount amount and then divide it by the total cost of the shirts.

Step 10: The total cost of 12 shirts is (2X + 150) * 4 = (2 * 550 + 150) * 4 = 2800.

Step 11: The total discount amount is the difference between the total cost and the amount Ram paid, which is 2800 - 5000 = -2200.

Step 12: Since the discount amount is negative, we can consider it as an additional cost. So, the overall discount percentage is (2200/2800) * 100 = 78.57%.

Therefore, the overall discount percentage allowed by the shopkeeper is approximately 78.57%.