I should start by saying I am a mature student (embarrassed!!) and it isn't strictly speaking homework but I am using the AQA website to work through past papers as I am self taught. I am struggling with a probability question and I find that using probability trees helps me. Well, the question is:
You have 100 people divided into 14 male managers and 26 male teachers, 8 female managers and 52 female teachers. What is the probability that you will select a male teacher and any female.
On my "tree" I have put the probability of males / females is 2/5 and 3/5 respectively.
I have then on my branch off the "males" I have divided males into 7/20 probability for manager and 13/20 probability for teacher. On my branch off the "females" I have divided females into 2/15 managers and 13/15 teachers.
I worked out then that probability of male teacher = 2/5 x 13/20 and any female = 3/5 x 2/15 plus 3/5 x 13/15
Needless to say my answer is wrong (AQA provide mark sheets). Please help!