Toby is filling his swimming pool for the summer. The pool normally takes 50 hours to fill. He knows his hose runs at 100 gallons per hour. Water costs 1 cent for 10 gallons. How many dollars does it cost to fill the pool? Let's think first. Chain of thought:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
The pool holds 5000 gallons of water because 50 x 100 = 5000. Every gallon costs $.001 because $.01 / 10 = $.001. It costs $5 to fill the pool because 5000 x $.001 = $5.
Therefore, the answer is 5.