Since a weekend getaway is a private good, if Musashi chooses to spend $300 on a weekend getaway, Musashi would get $300 of benefit from the weekend getaway and Sean wouldn't receive any benefit from Musashi's choice. If Musashi still spends $300 on a weekend getaway and Sean chooses to contribute $300 to the water fountain, Musashi would still receive the $210 of benefit from Sean's generosity. In other words, if Musashi decides to keep the $300 for a weekend getaway and Sean decides to contribute the $300 to the public project, then Musashi would receive a total benefit of $300 $210