Economics Homework HELP!!!!?

Question

Please refer to this website. I am stuck on problems 3 and 9, and i would like if you would let me know the other answers too, i just want a good grade. Thank you !!!

http://webclass.lakeland.cc.il.us/micro/pepsi.htm

Answer 1

3 - there will be only 10 cases supplied at this price, thus traded will be only 10 too (though shortage will be 40=50-10)

9 - there will be only 20 cases demanded at this price, thus traded will be only 20 too (though surplus will emerge 20=40-20)

1 - 10

2 - 50

4 - shortage

5 - 40

6 -  price will increase to $6 per case

7 - 40

8 - 20

10- surplus

11- 20

12- price will fall to $6 per case