The answer is 27 (hope this helps you)
The sum of any geometric sequence (if it converges, r^2<1) is of the form:
s(n)=a(1-r^n)/(1-r), a=initial term, r=common ratio, n=number of terms...
s(n)=30(1-0.4^n)/(0.6)
s(n)=50(1-0.4^n)
Since r<1 the sum of the infinite series is just:
s=50
I used the distance formula, the answer is 15
