Change each fraction to have a common denominator of 81
then just add them up
find the sum of the series
2/3+2/9+2/27+2/81+...
3 answers
a = 2/3
r = 1/3
S = a/(1-r) = 1
r = 1/3
S = a/(1-r) = 1
missed that nasty "..."