Answer :
To answer this let’s express it as an infinite series:
Sum from n=0 to infinity of .8(1/10)^n = .8/(1-1/10) = (8/10)/(9/10) = 8/9
Sum from n=0 to infinity of .8(1/10)^n = .8/(1-1/10) = (8/10)/(9/10) = 8/9