Tom and jerry are roommates at a college, and share their room for a total of 80 hours a week.Tom likes loud music, even when he's sleeping.His utility function is ut (gt, m) = gt + m, where gt is the amount of cookies he eats a week and m is the number of hours a week during which he listens to music when he is in the room.Jerry abhors music of any kind.Its utility function is u (gj, m) = gj - m2/12.Every week Tom and jerry receive two dozen chocolate cookies each from their families.They have no other supply of cookies.We can describe this situation by means of a graph very similar to that of the edgeworth box.We place the quantity of biscuits on the Y-axis and the number of hours of music on the Y-axis.Since cookies are a private good, the number of cookies Tom consumes per week plus the number of cookies jerry consumes per week has to be equal to 48.However, music is a public good.Both have to consume the same number of hours of music, whether they like it or not.Let's say that the height of a point in the box represents the total number of hours music is played in the room per week.The distance to the left side of the box represents "Tom's cookie amount" and the distance to the right side of the box represents "jerry's cookie amount".