a train leaves the city heading west and travels at 50 miles

a train leaves the city heading west and travels at 50 miles per hour. Three hours later, a second train leaves from the same place and travels in the same diresction at 65 miles per hour. How long will it take for the second train to overtake the first train?

Solution

The first train has already gone 150 miles when the second train takes off.
x = hours
50(x+3)=65x