The answer is
9n-2
d=9
1#=7
First we have to see in both cases what is the cost of one ticket
in the fist case 12.5/5=2.5
in the second case 20.16/8=2.52
therefore 5 tickets for 12.5 is the better deal
The best way to solve this is by giving a visual idea of the glass ornaments. so We will have letter G represent Green, O for Orange, B for Brown, P for Purple.
Sample 1:G,O,B,P
Sample 2:G,P,O,B
Sample 3:P,G,O,B
Sample 4:O,G,P,B
Sample 5:G,O,P,B
This is what you can do this should be the right amount of ways to arrange them.