A vendor purchases binder clips at 12 for Rs. 60. How many clips should he sell for Rs. 60 to earn a profit of 20%?

Step 1: Find the cost price of one binder clip. The vendor purchases 12 binder clips for Rs. 60, so the cost price of one binder clip is Rs. 60 / 12 = Rs. 5.

Step 2: Calculate the selling price for one binder clip to earn a profit of 20%. The selling price will be the cost price plus the profit. The profit is 20% of the cost price, so the profit per clip is 20/100 * Rs. 5 = Rs. 1. Therefore, the selling price per clip is Rs. 5 + Rs. 1 = Rs. 6.

Step 3: Find out how many binder clips the vendor should sell for Rs. 60 to earn a profit of 20%. Since the selling price of one binder clip is Rs. 6, the vendor should sell Rs. 60 / Rs. 6 = 10 binder clips for Rs. 60 to earn a profit of 20%.