A retailer buys a cooler for Rs 1200 and overhead expenses on it are Rs 40. If the coller for Rs 1550, determine his profit percent.
Cost price of cooler = Rs.1200
Overhead expenses = Rs. 40
Total cost = 1200+40 = Rs. 1240
Selling price of cooler = Rs.1550
Gain = 1550 - 1240 = Rs.310
= 
6