A building has a freight elevator as well as a passenger elevator. Both elevators shafts are 600 feet long. Both elevators start at the same time, t = 0. We have this information about the passenger elevator: 4 minutes after starting, it was at the top of its shaft, 600 feet up; 1 minute after starting, it was 150 feet up. This information is compactly described by the ordered paired (4, 600) and (1, 150). With a similar notation, we have the following information about the freight elevator: (2, 350) and (3, 100). Exactly when (if ever) are both elevators at the same height, and exactly what is that height? Note: do not approximate.