#### Answer

Estes offers the best price by 12 dollars.

#### Work Step by Step

Estes offers boat rental for 9 dollars for 15 minutes. This makes it 4(9) = 4(15) or 36 dollar per hour (60 minutes), Three hours would cost 108 dollars.
SHip and SHore offers boat rental for 20 dollars for 30 minutes. This makes is 40 dollars per hour. Three hours would cost 120 dollars, '
Estes offers the best price by (120 - 108) - 12 dollars.