Question 892097
i was able to solve this graphically.


the solution is n = 20


C(20,8) = 125970


C(20,12) = 125970


C(20,18) = 190


the graph is shown below:


<img src = "http://theo.x10hosting.com/2014/081109.jpg" alt="$$$" </>


i tried to solve it algebraically and ran into great difficulty so i settled for what i could do which was the graphical solution.