a car leaves a train station traveling west at a speed of 40 km per hour. A train leaves after 3 hours later traveling west at 120km per hour. At what time will the train catch up? How faar from the station will the train be when it catches the car?

Solution:

Time: t after the second train leaves

so we get the equation below:

120t-40t= 3*40

t= 1.5

so 1.5 hours after second train leaves, they catch up

The distance is 1.5*120 = 180 km.