If the speed of a boat in still water is 20 km/hr and the speed of the current is 5 km/hr, then the time taken by the boat to travel 100 km with the current is
Naveen purchased a gas cylinder and a stove for Rs.4500. He sold the gas cylinder at a gain of 25% and the stove at a loss of 20%, still gaining 4% on the whole. Find the cost of the gas cylinder.