Question 796613
At 10 AM, the 46 mph train was traveling for 2 hours, and the 69 mph train was traveling for 1 hour.


rate*time= distance for the 46 mph train,
rate*time= distance for the 69 mph train, but 
different values for each.


This uses subtraction because we want the difference in the two trains' distances.
{{{(46*2-69*1)=92-69=highlight(23)}}} miles