Goal Seek Help

[siddhs]

Hi Everyone !
This is my first ever post on this site and feel great to be here....offcourse with some help first up :p...

Anways...to be honest this is my assignment and I have no idea about Goal Seek...I have to write a formula...Although its simple but I am just not able to sort it out ....whats more is that tommorow I have to submit this assignment and I very badly need help....so please please help me get through this .......

the question :
Use goal seek function to deterine how many CDs with a purchase price above $12 could be purchased if the company decides to spend $100,000 in total on promotional CDs. Remember that all the promotional CDs still need to be purchased, not just those with a purchase price of $12 or more.

The rates of CDs are : (1) 13.75
(2) 12.75
(3) 12.5
(4) 12.5

I still dont know where I have to put formula and where I have to put the target value...every time i use goal seek and it says interation didnt find any result

P L E A S E help me...
Thanks and regards,
Siddhs

[siddhs]

guysssssssssss pls plssssss