Answer:
a) 
And replacing we got:

b) 
And then the expected value would be:

Step-by-step explanation:
We assume the following distribution given:
Y 0 1 2 3
P(Y) 0.60 0.25 0.10 0.05
Part a
We can find the expected value with this formula:

And replacing we got:

Part b
If we want to find the expected value of
we need to find the expected value of Y^2 and we have:

And replacing we got:

And then the expected value would be:

The concert director can choose the new members by holding try outs to take the the possible candidate’s skills, performance and professionalism into consideration to be a part of the large show. Another way is by voting amongst other people in their school to see who the audience would be excited to see preforming in the show.
Find the common denominator of 3 and 6. which is 6. now just subtact 2 and 1 which is 1. ur answer is 1/6
306+122=428
Because you add 6 & 2 in the ones place which is 8.
then 2 and 0 which is 2.
finally 1 and 3 which is 4
I'm assuming you mean triangle angles?
If so, all angles add up to 180 so combine them and set them equal to 180.
51+82+5x+2=180
135+5x=180
5x=45
x=9