Box a contains 2 black marbles and 1 white marble. box b contains 1 black marble and 1 white marble. a marble is randomly selected from box a and put into box b. then a marble is randomly selected from box b and put into box a. after all this, what is the expected number of black marbles in box a?

Mason and christian go to the movie theater and purchase refreshments for their friends. mason spends a total of $45.75 on 3 bags of popcorn and 6 drinks. christian spends a total of $71.50 on 6 bags of popcorn and 4 drinks. write a system of equations that can be used to find the price of one bag of popcorn and the price of one drink. using these equations, determine and state the price of a drink, to the nearest cent.