Random Math Questions

[BlasianAsian]

Ok. I hate probability. I can't tell whether to use permutations or combinations or when you have to divide this thingy by that thingy and only a certain number of thingies can be used when this theory is applied to the problem yada yada yada.

So, once again, more questions! =D

Fifteen people try out for a baseball team. In how many different ways could they select...
a) The pitcher and the catcher?
b) The three outfielders, AFTER the pitcher and the catcher have been selected?
c) The 1st, 2nd, and 3rd basemen and the shortstop, AFTER the pitcher, catcher, and three outfielders have been selected?

I have NO idea how baseball works, making this problem even harder for me, lol. Halp, plz?

[nsguy1350]

a. You can pick 15 pitchers, then you have 14 options for the catcher, or 220.
You could also do 15P2, since order does matter (me being pitcher and you being catcher is different than you being pitcher and me being catcher.)
b. You have 13 choices, then 12, then 11, so 1726?
Or, is it 220 x that, since there are 220 pitcher-catcher combos? I think it says "after", so you just do 13P3, which is 13 x 12 x 11, the first choice.
c. 10P4? Which is 10 x 9 x 8 x 7, or 5040.

[BlasianAsian]

Ok, thx!