Oops. I didn't know why I squared 4/30, which is better since it is once every ~7.5 months. Its not as non-random as csomar suggested, since you could have the

Oops. I didn't know why I squared 4/30, which is better since it is once every ~7.5 months. Its not as non-random as csomar suggested, since you could have the day off any day of the week. However you usually get a day off once a week. I guess it should be better estimated at 1/7 chance of having the same day of, per week. That gives roughly 1 day every 2 months