Answer:
There are 729 possible results are there for the series
Step-by-step explanation:
If we have n trials, each with m possible outcomes, the total number of possible outcomes is:

In this question:
6 games(trials), so
.
Each with three possible outcomes, so 
Then:

There are 729 possible results are there for the series
Setting it up, we have Dan + Bret + Maria all saving 600.00
Dan = 2B
Bret = B
Maria = B+60
2B + B + B + 60 = 600
4B = 540
B = 135
Dan = 2(135) = 270
Brett = 135
Maria = 135 + 60 = 195
Use the fomula a_(n)= a_(1)+ d(n-1)
I divided 56 by 4 to see how much per CD Brad payed. This got me $14. $42 divided by $14 is $3, so he can buy 3 CDs.