Thread: Train's Average Speed

A cattle train left Miami and traveled toward New York. 14 hours later a diesel train left traveling at 45 km/h in an effort to catch up to the cattle train. After traveling for four hours the diesel train finally caught up. What was the speed of the cattle train’s average speed?

Originally Posted by magentarita

A cattle train left Miami and traveled toward New York. 14 hours later a diesel train left traveling at 45 km/h in an effort to catch up to the cattle train. After traveling for four hours the diesel train finally caught up. What was the speed of the cattle train’s average speed?

The diesel goes 45 km/h so in 4 hours will have gone 4(45)= 180 km. Since it started 14 hours after the cattle train, 4 hours after the diesel started will be 14+ 4= 18 hours after the cattle train started. If we let v be the average speed of the cattle train, in km/h, in 18 hours, it will have gone 18v km. Since the diesel caught up to it then, they have gone the same distance: 18v= 180 so v= ?

Originally Posted by HallsofIvy

The diesel goes 45 km/h so in 4 hours will have gone 4(45)= 180 km. Since it started 14 hours after the cattle train, 4 hours after the diesel started will be 14+ 4= 18 hours after the cattle train started. If we let v be the average speed of the cattle train, in km/h, in 18 hours, it will have gone 18v km. Since the diesel caught up to it then, they have gone the same distance: 18v= 180 so v= ?

I thank you.