Question 333242
find the sum of the infinite geometric series: 9 + 6 + 4 + ...

sum of infinite = a/ (1-r)
common ratio = 2nd / 1st 
therefore 
common ratio= 6/9=2/3

a=9,r=2/3
sum =a/(1-r)
    =9/(1-2/3)
    =9/(3-2/3)
    =9/1/3
    =9*3/1
    27