A postal truck leaves its station and heads for Chicago aver

A postal truck leaves its station and heads for Chicago, averaging 40mph. An error in the mailing schedule is spotted and 24 min. after the truck leaves, a car is sent to overtake the truck. If the car averages 50mph, how long will it take to catch the postal truck?

Solution

If the give two speeds are v1(< v2) with distance D,then
the time for the 2nd vehicle to overtake the 1st vehicle is
T = D/(v2 - v1).
Now,D = 40* 24/60 = 40* 2/5 = 16 miles,
Hence, T = 16/(50-40) = 1.6 hours