Permutation / Computation Guide

parikhs
Fri, 02 Sep 2005 08:40:05 +0000

Thanks for trying to explain, but I still don’t get it. Maybe I’m overanalyzing or something, but I’m confusing myself. I understand how 2 can’t be placed in either end so of the 5 cards…1 of 4 can be placed on the left and 1 of 3 can be placed on the right. Then you’re left with ‘2’ card and 2 others. Those can be placed anywhere in the middle 3 slots. I just don’t understand how you’re supposed to multiply / do the math work once you understand that. Nor do I understand the difference between permutation / combination and what nCr and nPr mean (the n / r means?). Thanks for the help.