Question

your car stereo can be programmed to hold six radio stations of your choice. There are nine stations you really like. How man different ways can you program your six buttons with different collections of your favorite stations? (a different ordering of the same six stations counts as different programming.) This is my guess 9!/(9-6)! = 9!/3! = 9 * 8 * 7 * 6 * 5 * 4 = 60,480.

Answer 1

Well you can use a Combination which would mean it would be 9 nCr 6, so I got 84. because the stations can't be repeated in one sequence, but order doesn't matter.