TSA 2009 · Question 12 · Rates
SaveIonnais lives at the bottom of a very steep hill. Worse than that, the post office is at the top. Every Thursday he must go there to collect his pension. He can only walk at 2 km per hour uphill but manages 4 km per hour downhill. The round trip, excluding the wait at the post office, takes him 4½ hours.
How far is it from his house to the post office?