2 Problems - HELP!!!

:confused: new to this whole stats thing , and ive been going over these 2 questions for ages and cant come to a conclusion , someone plz help , show steps . THANK YOU :eek:

There are 15 red balls, 12 blue balls and 11 green balls in a box. If someone takes out 3 of
them, throws them to you, and you place them in your pocket, what is the probability you will
get exactly two red balls?


You estimate that you know 80% of the material for this exam. That is to say that for any
multiple choice question there is an 80% chance you will get it correct. If we assume that the
binomial distribution is appropriate, what is the probability that you will get at least 13 of the
first 15 questions correct?