I'm studying for an intro Physics exam and encountered this problem on my study guide: "A vector of magnitude 20 is added to a vector of magnitude 25.The magnitude of this sum can be: A) 50 B) 12 C) 3 D) zero E) none of these are possible. " The professor told us the answer was B), but I don't understand why. I understand that the maximum you can get with these 2 vectors is the sum (20+25=45) and that the minimum you can get is the difference (25-20=5). I don't get where the 12 is coming from though. If anyone could point me in the right direction, that would be great. Thanks!