I really need help. I need to answer this 3 questions

Question

My first is this:

Pizzas CD's
------ ------
0 15
1 14
2 12
3 9
4 5
5 0
Using this information, calculate the marginal benefit and draw the marginal benefit curve.
****I really need to know how to calculate it.

My second question is: which is totally unrelated.

2.How did the catastrophic events of 9-11 affect the marginal benefit and marginal cost diagram? (Hint: One of the curves shifted). Draw a diagram showing the post-9-11 marginal benefit and marginal cost diagram. What is the new efficient quantity of security services? How does this new point relate to the discussion in the Wall Street Journal article about the costs being imposed on the public from enhanced security?

***I know i asked this second one already but this time i just need a bit clarification.

****Why would the Marginal benefit shift to the right and how do we know how much it shifts by to determine the new efficient quantity???

Now my final question is this:

3.Suppose a new technology becomes available that cheaply and easily detects “intent to harm” by remote sensing of physiological indicators. Unobtrusive (and inexpensive) detectors would immediately alert authorities to the presence of terrorists. With the same amount of land, labour and capital as before, this technology would enable us to provide more “units of security”. What would be the effect of this new technology in the diagram with the production possibilities frontier and in the diagram with the marginal benefit and marginal cost curves? What happens to the efficient quantity of security?

**** If that happens then would x-axis of the PPF shift outward and in relation to the marginal benefit and cost, both curves will shift outward and to the right because the cost is increasing as well as the benefit.

This is the PPF for questions 2 and 3
*img170.imageshack.us/img170/7894/ppfiq2.jpg

plz help