Residence definition. Susan owns a houseboat. During the year, Susan and her friends partied on the houseboat for $20$ days and went home at $11$:$00$ pm each night. She rented out the houseboat to strangers for overnight trips at full rental rates for $250$ days. She also rented out the houseboat for overnight trips to her friends at a $50\%$ discount for $10$ days. None of these days overlapped $($e$.$g$.,$ strangers did not move out on the same morning when friends moved in in the afternoon$).$ To determine whether the houseboat is a $$residence$$ for tax purposes, how many personal use days and how many rental use days were there?