Joined: 20 Jul 2009
Schools: Kellogg; Ross ($$); Tuck
, given: 6
Re: probability from Gmat prep [#permalink]
21 Sep 2009, 11:35
let's say the sizes are medium (M) and small (S)
we have blue-medium (Bm), Blue-small (Bs), Gm, Gs, Ym, Ys, Pm, Ps.
if we consider the packages that consists of 3 notepads of the same size and same color, we have 8 possible packages. (1 pack of Bm, 1 of Ym, 1 of Bs etc...)
If we consider the packages that consists of same size and different color, we have to choose 3 out of four (Bm, Ym, Gm, Pm) that is 4 possibilities and the choose 3 out of four (Bs, Ys, Gs Ps) 4 possibilities again.
So the number of packages is 8+4+4=16