This is probably quite simple, but for some reason, I am having a problem with it.

Ok, I'm trying to find x in this series of numbers

1 , 1x , 1x^2 , 1x^3 , ..... , 0.2

the sum of all numbers in the series = 5

I would assume the solution has to do with logarithms.

If someone could show me how to find the solution to this, I would greatly appreciate it, thanks.