You and some friends decide to take a canoe trip down the Wood River. The stretch of river you are traveling flows at a roughly constant speed of 2 mph. You are able to paddle your canoe at a speed of 3 mph relative to the water. Unbeknownst to you, shortly after you set off down the river, your keys fall into the river. Fortunately, they are attached to a floating key chain. After two hours of paddling, you notice they are missing. You turn around and paddle upstream looking for them. About how long will it take you to find your keys? Assume they move along steadily with the current and that you spot them as soon as they are within a few feet of your canoe.