posted by Jonny on .
A car started out from Memphis toward Little Rock at the rate of 60km/h. A second car left from the same point 2 hours later and drove along the same route at 75km/h. How long did take the second car to overtake the first car.
The distance traveled by car A and car B is the same
distance = speed * time
car B traveled 2 hours less than car A. At time t
60t = 75(t-2)
60t = 75t - 150
15t = 150
t = 10
so, in 10 hours, car A traveled 600 km
in 8 hours, car B also traveled 600 km
The answer is, it took car B 8 hours to overtake car A.