A certain identification code consists of 6 digits, each of which is chosen from 1, 2, ..., 9. ...The same…
Here's a simple solution to the classic "For a certain race, 3 teams were allowed to enter 3 members each"…
GMAT Combinatorics: The Ultimate Guide to GMAT Factorials -- the Three-Question Method If we don’t get the concept of Factorials…
GMAT Combinatorics Questions: Permutations vs. Combinations (plus Shorthand!) As noted above, this is simply a clipped factorial. Let’s take the…
GMAT Combinatorics: an Introduction Ever wonder why GMAT Permutations and Combinations seem to hard to learn? There's no good reason--that's…