Speed

A freight train is travelling at a constant speed of \(72\) km/h.

1. A passenger train is travelling towards the freight train at a constant speed of \(108\) km/h. A passenger on the passenger train observes that it takes \(21\) seconds from the moment the two trains meet each other until the two trains completely separate. Given that the passenger train is \(450\) m in length, find the length of the freight train.
2. The freight train is entering a tunnel. Given that it takes \(1\frac{2}{3}\) minutes for the freight train to completely leave the tunnel, using your answer in (i), find the length of the tunnel.