The time it takes to drive 30 miles depends on how fast you're driving.
For example if you're driving 60 MPH and are driving 30 miles then you would cover 1 miles in 1 minute.
So to drive 30 miles at 60 miles per hour would mean that it takes you 30 minutes to cover or drive 30 miles.
If you drove at a speed of 50 MPH or less then it would take you around 55 minutes to an hour to drive 30 miles depending on your driving speed.
The faster you drive the more miles you cover in a faster time and the slower you drive the less miles you cover in the same amount of time.
Although you should never speed.