Can someone help me find the equation to this story problem?

Question

An express train and a car leave Chicago at the same time and head for a town 280

miles away. The speed of the express train is twice the speed of the car. The train

arrives 4 hours ahead of the car. Find the speed of the train.

I've try doing it many times, but the equation i use seems wrong which is why I'm always getting the wrong answer. Thank You.

Answer 1

Let train travel at t miles/hour and car at c miles/hour.

Then t=2c.

Time taken by train (in hours) is 280/t = 140/c.

Time taken by car (in hours) is 280/c.

We are told that

4+(140/c) = 280/c

=>4c=140

=>c=35

=>t=70

So the train travels at 70 miles/hour (and the car at 35 miles/hour).