posted by Jen on .
A disc jockey has 12 songs to play. Seven are slow songs, and five are fast songs. Each song is to be played only once. In how many ways can the disc jockey play the 12 songs if:
*The songs can be played in any order.
*The first song must be a slow song and the last song must be a slow song.
*The first two songs must be fast songs.
a) played in any order = 12!
b) 1st and last slow, = 7(10!)(6)
.... 7 in the first spot, 6 in the last spot, leaving 10 for the rest
c) 1st two must be fast = 5(4)(10!)
gosh that's so confusing :(