Find the probability that a molecule does not leave immediately. Show that the expected time to leave

Question:

Find the probability that a molecule does not leave immediately. Show that the expected time to leave in this case is 1 + E(T).
The expectation of the geometric can be found using a clever trick.
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...