In an online game the chance of succeeding at an action starts at 5% and goes up 5% every time the action fails.

Upon success the chance resets back to 5%.

(So you know how they say a die has no memory of prior rolls? Here it does.)

The question: How many attempts do I need to have a 50/50 chance of success?

Alternate question: What fixed percent chance would duplicate the overall success rate of this system? (Over many rolls.)