A skier wears a jacket filled with goose down that is 15 mm thick. Another skier wears a wool sweater that is 4.0 mm thick. Both have the same surface area. Assuming the temperature difference between the inner and outer surfaces of each garment is the same, calculate the ratio (wool/goose down) of the heat lost due to conduction during the same time interval. Isn't heat flow directly proportional to the distance?