700 miles in 12 hours means you are traveling at a speed of about 58.3 miles per hour. However while that is a reasonable speed for good fuel economy (the faster you go the more gas you use), how much gas you will need depends on the MPG performance of the car. Some cars only give you 20 miles per gallon an other modern cars will give you 60 or 70 miles per gallon.
A good diesel will do about 60 miles per gallon and thus would need 12 gallons to go 700 miles.
Next time when asking questions please try and be specific about what you want to know and supply ALL (eg the MPG performance) that is needed in the question. For instance the time it took (12 hours) is only marginally relevant in this case.
46.875 Gallons
41 gallons
40 gallons
1158/20 = 57.9 gallons
If you get 25 miles per gallon you will use 72 gallons.
Basic mental arithmetic !... 52.85 gallons.
You need 699/30 = 23.3 gallons.
At 20 miles per gallon, it would take 9 gallons to travel 180 miles.
350 / 18.5 = 19 (18.9189) gallons are needed.
468 miles at 12 miles to the gallon = 468/12 = 39 gallons. 12 mpg!
1057/31 = 34.1 gallons.
You will need 1.107 gallons of fuel.