# Math Help Needed

Ok so i took elementary statistics during the fall and got an A in it, im now in business statistics, which so far has very little calculations going on. My wife is taking elementary statistics now and we came across this problem that we know how to do the long way, but are trying to find the short was to do it in the TI-83. Here is the question.

A landscaper wants to plant 4 oak tree, 8 maple trees, and 6 poplar trees along the border of a lawn. If the trees are evenly spaced apart, in how many distinguishable ways can they be planted.

The long way by hand on this one is this:

18!/8!*6!*4! = 9,189,180

Her statistics text book seriously sucks and makes things way harder than they should be. I know there is a quicker way to do this in the calculator, does anyone know? Does it have something to do with Math>combination or Math>permutation functions? I tried:

18 C 8 * 18 C 6 * 18 C 4 but didnt work, man i just got a little to rusty lol.

thanks for any help :geek: