How long does it take to ride a longboard for 3 miles?

Well...it depends on how fast you're riding your board. I used to longboard to school which is about 3 hours away and it only takes me about 10-15 minutes and that depends if I'm going faster or slower than usual or if the street lights are extra long etc. I probably go faster when I have new bearings, too.

The slope best fit isc. 1/6 mile per hour