Determine whether the infinite geometric series converges or diverges. If it converges find its sum.

To go from term to term, multiply by 5.

To be a convergent geometric series, the number that you multiply by must be a fraction between -1 and 1 (and not including either -1 or 1).

Since the common ratio (the number you multiply by) is not a fraction between -1 and 1, it doesn't converge.