How much money on gas would you spend from Miami to Los Angeles?

Mapquest indicates that the total miles from Miami to LA are somewhere around 2746.83. Let's round up to 2750.

For the sake of this answer, let's say your vehicle gets somewhere around 30 MPG for highway driving. That's probably not accurate but you can figure out the REAL mileage later.

And let's say you average $2.00 per gallon for fuel since it can be quite expensive purchasing gasoline on the highway..

2750 miles/30 miles per gallon = ABOUT 92 gallons.

92 Gallons times $2.00 per gallon = $184 in fuel costs.

The GENERAL formula would be:

((Expected miles to travel) / (fuel economy of the vehicle in MPG)) * (average price per gallon of fuel)

OR

T=M/E*C

Where

T=Total cost of fuel

M=Miles expected to travel

E=Fuel economy of the vehicle in MPG

C=Cost of fuel per gallon