An express train takes \(1 \ hr\) less than an passenger train to travel \(315 \ km\) between Mysore and Bangalore (without taking into consideration the time they stop at intermediate stations). If the average speed of the express train is  \(20 \ km/hr\) more than that of the passenger, find the average speed of the two trains.
 
Answer:
 
The average speed of the passenger train is  \(km/hr\)
 
The average speed of an express train is  \(km/hr\)