a. The marginal densities

and

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

The area of a rectangle can be found by multiplying the length times the width, or A = l * w. The perimeter of the rectangle can be found by adding together the length twice and the width twice. From the given information, we know that l = p and w = p + 4, where l represents the length of the rectangle and w represents the width of the rectangle.
A = l * w = p(p+4) = p^2 + 4p
P = 2l + 2w = 2(p) + 2(p+4) = 2p + 2p + 8 = 4p + 8
Therefore, the area of the rectangle is p^2 + 4p and the perimeter of the rectangle is 4p + 8.
Hope this helps!
If you would like to know if is 5/12 greater than 0.44, you can calculate this using the following step:
0.44 = 44/100 = 11/25 = 132/300
5/12 = 125/300
Result: 0.44 is greater than 5/12 (0.44 = 132/300 > 5/12 = 125/300).
Well n could equal 9 and they would both be the same thing but if n equaled 6 then it would be less but if it equaled 11 then it would be over 12