Shortest distance

Point me in the right direction with this problem since I have no idea on how to tackle it.You're given 4 set of coordinates in R^3 that form a tetrahedron, then another 4 set of coordinates in R^3 that form another tetrahedron.
How do I find the smallest distance from the surface of one tetrahedron to the other?

>>9
The specification I was given requires 2 decimals of precision. Ignoring surface to surface still gives me that precision?

>>10
This is an assignment from Algorithms and Data Structures 2. I have no idea how to implement this. I'm trying to do this using just the stuff I learned in Linear Algebra first semester.