Question 165431
Tom's speed = 25 mph
Mary's speed = 30 mph


Let Tom's time = t hours
so, Mary's time = (t - (10/60)) hours


when Mary and Tom meets:
Mary's distance = Tom's distance
30*(t - 1/6) = 25*t
<=> 30t - 5 = 25t
<=> 30t - 25t = 5
<=> 5t = 5
<=> t = 5/5 = 1


so, Mary can catch Tom 1 hour after Tom left,
that means, she can catch Tom at 2:30pm