I have the following question as practice for an upcoming test:
A website suggests that men think about sex an average of $15$ times per day.
Let $x$= the number of hours that pass between successive thoughts of sex, = $1.6$
At least $1.6$ hours have passed since the last thought of sex. What is the probability that in total, at least $3.2$ hours will pass until the next thought of sex?
I thought since Exponential Distributions are memoryless, that this would just be $P(x \ge 3.2)$, but apparently this is wrong.