Sales acting like this would produce a geometric sequence with a common ratio of 90/100 or 0.9 because each term would be 0.9 time the previous term.
The sum of a geometric sequence is:
s(n)=a(1-r^n)/(1-r), a=initial term, r=common ratio, n=term number, in this case:
s(n)=495000(1-0.9^n)/(1-0.9)
s(n)=495000(1-0.9^n)/(0.1)
s(n)=4950000(1-0.9^n) so
s(6)=4950000(1-0.9^6)
s(6)=$2630632.95
