To find the ratio, you have to get a common base. First, convert 3.5 hours into minutes to get a common base (210 min).simplify to get a simplified ratio.
14 km : 21 min (car, divide each by 10)
3 km : 5 min (train, divide each by 10)
The LCM of the times (21 and 5, since you want to find the ratio of the speed of the car to the speed of the train) is 105.
Multiply 14 and 21 by 5, and you get the ratio
70 km : 105 min (car)
Multiply 3 and 5 by 21, and you get the ratio
63 km : 105 min (train).
Now that you have common bases, you can find the car speed to the train speed.
**Edit: you can simplify this to 10:9
The ratio is
The car travels at
For the train, you have to make the conversion to per hour.
Therefore, The train travels at
This is the ratio, which can be simplified to