A system has one each of two different types of components in joint operation. Let X and Y denote the random lengths of the lives, in hundreds of hours, for components of type I and type II, respectively. The joint density function is:

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.

Hi my sisters and brothers can tell me the answer because i don’t understand the question

Abag contains 3 red marbles, 2 blue marbles, and 2 green marbles. one marble is picked, then another marble. assume that the selections are made with replacement. a) find the probability of picking two red marbles with replacement. b) find the probability of picking a red marble and a blue marble. assume the selections are made without replacement. c) find the probability of picking two red marbles without replacement. d) find the probability of picking a red marble and a blue marble without replacement.