Question #a8f53

1 Answer
May 22, 2015

To make sure I have your data right:

There are 35 students, 21 are female, thus 14 male.

to solve for a)

we fist solve for what the probability of getting a female main rep.
which is the first student selected.

thus we take #1# student from the class of #35# and the probability that the student is female is:

#P#female main rep# = 21/35#

now one student is taken, and we left with #34# to select the alternative, which would looking at the chances its a male:

#P#male alternative #= 14/34#

we know here that #P(A nn B) = P(A).P(B)#

thus the answer to a) would be:

#(21/35)(14/34) = 0.247# or #24.7%#

now for b)

we will use the same reasoning, thus the first selected will be #1# male:

#P#male main rep#=(14/35)#

and then we are selecting another male, which there is now #1# less as we chose #1# as the main rep, and can not be chosen again, so we have:

#P#male alternative #=(13/34)#

which will lead us to our answer to b) as:

#(14/35)(13/34) = 0.153# or #15.3%#