Please provide Handwritten answer.

He has a 20% chance of misplacing his pen and having to start using another new pen.

QUESTION 4 (3 POINTS) Professor Brainstom was a very absent-minded fellow and prone to losing pens. On any given day, he has a 20% chance of misplacing his pen and having to start using another new pen. On average, on how many days would he use a particular pen assuming that he only starts using a new pen because he lost the old pen. Show all your work. average no. of days on which a pen is used=