Say we have a random variable A and another random variable B. A is described as a row of 50% chances between either getting a beer or a coffee, that have no influence on each other. Let's say the expectation of A is time when we first get a beer. B is A+1. Is it correct, that E[B] = E[A] + 1. And since E[A] = 2, E[B] = 3