Jose left the White House and drove toward
the recycling plant at an average speed of 40
km/h. Rob left some time later driving in
the same direction at an average speed of 48
km/h. After driving for five hours Rob
caught up with Jose. How long did Jose
drive before Rob caught up?

Question

Jose left the White House and drove toward
the recycling plant at an average speed of 40
km/h.  Rob left some time later driving in
the same direction at an average speed of 48
km/h.  After driving for five hours Rob
caught up with Jose.  How long did Jose
drive before Rob caught up?

watchmath · Answer

Suppose Jose left y hour earlier than Rob
After 5 hours here are the distance traveled by the two
Jose's distance= 40y+40(5)=200+40y
Rob's distance = 48(5)=240
The two distances are equal
200+40y=240
40y=40
y=1
So Jose drove 1 hour earlier.
It means when Rob caught up , Jose already drove for 5+1=6 hours.