
Explanation:
Since we have given that
The prices of three t-shirts styles i.e $24, $30, $36 with their probability is given by

As we know that,


Now,

and

So,

So, the expected value of a t-shirt = $31.
Answer:
3
Step-by-step explanation:
10.50 x 3 = 31.5
15 x 13 = 195
195 + 31.5 = 226.50
Answer:
His wife gets $336 more than his son.
Step-by-step explanation:
Colin and Brian:
Ratio of 4:1.
So Colin gets
of the prize.

Colin got $1680. Dividing between himself, his wife and their son:
Ratio of 2:5:3.
So Colin gets
, his wife gets
and his son gets 
Wife:

His wife got $840.
Son:

His son got $504.
How much more does his wife get over their son?
840 - 504 = 336
His wife gets $336 more than his son.