Now have 100 posts. Ask me anything!

[JCSR]

In that equation you are solving for the time that the first train is in motion, but the problem wants to know how long it takes the second train to make the intercept. You have that in your equation (x - (1/2))

thus (5.5 - 0.5) = 5.0


Edit: backtest Train one covers 50mph x 5.5 hrs = 275 miles. How long would it take a train going 55mph to cover the same distance? 275/55 = 5 hours

I agree. It depends on when you start the clock