[Question]: Six bottles of 2 liters of water cost $12. What is the price of 1 liter of water?
[Answer]: Each bottle of 2 liters of water costs $12 / 6 = $2. So the cost of 1 liter of water is $2 / 2 = $1.
So the answer is 1.

[Question]: James can buy a new computer for $600 and have it last 6 years, or buy 2 used computers for $200 each that each last 3 years. How much money will he save by picking the cheaper option?
[Answer]: First find the cost of the two used computers: $200 / computer * 2 computers = $400. Then subtract that cost from the cost of the new computer to find the savings: $600 - $400 = $200.
So the answer is 200.

[Question]: Bob is building a garden on his land, and he wants it to be fenced in to keep out varmints. The garden is a rectangular plot 225 feet long by 125 feet wide. He also wants to have a small 3-foot wide gate to walk through and a larger 10-foot wide gate to move his gardening equipment through. How much fencing is Bob going to need to fence in his garden, taking into account the two gates?
[Answer]:

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 perimeter of the garden is 2 * 225 + 2 * 125 = 450 + 250 = 700 feet. Minus the two gates, he will need at least 700 - 3 - 10 = 687 feet of fencing.
So the answer is 687.