The speed of the remote control carriage is uniform = 3.5m / s.
The elapsed time is 5 minutes.
You can use the formula
speed = distance / time.
Clearing the distance, which is what we want to find, we have:
distance = speed*time.
However, the speed is in units of seconds and the time in units of minutes. To perform the operation we need to have everything in the same units.
So.
5minutes x 60seconds / 1minute = 300 seconds
Finally:
distance = 3.5m / s * 300s = 1050 meters.
The remote control car traveled 1050 meters