If traveling through a white circle takes that many minutes, and black circles represent backwards jumps in time that save 5 minutes, what's the shortest trip through this map?
From the spanish MENSA site.
No matter how you go, you have to go thru 14 (first circle) and 13 (last circle). Also, you go through exactly 4 black circles no matter what path you take. So, we're looking for the 3 other white circles--in addition to the 14 and the 13--that can be reached on a path that moves north or east (only) with the smallest sum. That would be 12, 10, 12 traveling north as far as possible, then east.
That trip takes 41 minutes (same answer as pcbouhid).