Please Help me: I am taking Praxis II and I need some help with a few math problems (mid-level)?

I am sure that these are simple enough, but I want to make sure that I understand these. I took a practice test and I thought that I had done fairly well on it, but I missed 8 out of 30! I have a lot riding on this test, I have one chance to take it before the fall and if I do not pass, it will delay my graduation for one year. I feel really dumb, I have A's in all of my math classes, but this test seems to be hard for me. I will think that I have a grasp on it, but I have already failed it once. All help is appreciated and please make sure to explain your answer. Thank you!

1.) The population of country X is 0.36 billion persons, and the population of country Z is 12 million persons. The population of country X is how many times that of country Z?

2.) The 40 eggs in a box weight a total of x pounds. What is the average weight per egg for the eggs in the box, in ounces? a) x/640 b)56/x c)56x d)2x/5

3.) Shows a right triangle: side a=x side b=4 side c=w

What is x^2 in terms of w?

4.) Shows a graph with a line segment with the coordinates a(1,1) and b(4,4)

If line segment AB is flipped over the x-axis such that point A becomes point C and point B becomes point D. What are the coordinates for C and D?

4.) It shows three circles with one triable that goes through all three of them and they are arranged in such a way that the sides of the triangle makes up the radius of each circle. The problem reads:

Each circle is tangent to the other two circles. The points X, Y , and Z are the centers of the circles. If the circles have radii of 3, 4, and 5, respectively, what is the perimeter of triangle XYZ?

5.) P=XY

What would happen to the value of P in the equation above if the value of X was increased by 10% and the value of Y was decreased y 10%?

6.) A 4-inch by 6-inch photograph is to be enlarged by proportionally so that the 4-inch side expands to 5 inches. What would be the new length, in inches, of the 6-inch side of the photograph?

7.) A set consists of the letters A,B,C,D,E, and F. If order is not important, how many two-letter subsets are possible?

I know this is a lot of questions, but I really need help to make sure that I understand how to work them. I really do appreciate your time and help. Thank you in advance.