The answer is...
The twenty dollar tip, that was given to the Dock Hand, shouldn't have
been
added to the $270 price that the couples paid for the boat.
It should have been subtracted. The tip was already included in the $270
paid.
$90 + $90 + $90 = $270
- $20 (tip) = $250 (The actual cost of the boat)
$250 (Actual cost of the boat) + $50 (Amount returned by boat owner) =
$300
$300 was the initial cost of the boat.
