A train started at 9 AM from a station A with a speed of 72 km/hr. Another train after two
hours started from the station B towards A with a speed of 90 km/ph. The two trains are
expected to cross each other at 1.30 PM. At 12 noon because of the signals both the trains
reduced their speeds by the same quantity and they crossed each other at 4.30 PM. Thespeed of the train, after 12 noon, that started from the station A, is