A train travels at a certain average speed for a distance of \(80 \ km\) and then travels a distance of \(90 \ km\) at an average speed of \(5 \ km/h\) more than its original speed. If it takes \(4\) hours to complete the total journey, what is its original average speed?  
 
Answer:
 
The original average speed of the train is \(km/h\).