Your answer is B!
I hope this helped!
Answer:
It's nine plus negative three
a. The marginal densities

and

b. This can be obtained by integrating the joint density over [0.25, 1] x [0.5, 1]:

The areas will be in the ratio 1 : 1.5^2 = 1 .2.25
The area will be larger by a factor 2.25.
The first thing to do is to work out the biggest number that goes into bother 24 and 3. As the only that goes into three- other than 1- is itself, one can assume this is the number we are looking for.
Next, divide bother numbers by 3.
24 / 3 = 8
3 / 3 = 1
You now take 3 out of the brackets, and leave 8 and 1. 24x / 3 = 8x.
3(8x + 1)