A gallon of milk weighs eight pounds, so you wouldn't try to carry three or four gallons home on your bicycle. gasoline is a bit less dense than milk—oil floats on water—and 6 pounds per gallon of gasoline is about right. a typical u.s. "car" (whatever it is we drive—averaging somewhere between a prius and a hummer, and including a lot of pickup trucks and minivans) gets about 20 miles per gallon, and drives about 12,000 miles. so, how many gallons of gas per year?

Answer:600 gallons / yearExplanation:The single question is about the amount of gallons of gas per year a typical U.S. "car" uses.The relevant information to find how many gallons of gas per year a typical U.S. "car" uses is:unit consumption of gas per gallon: 20 miles per gallon: 20 miles / gallon, andnumber of miles the car drives: about 12,000 miles / yearThe rest of the statement is anectodic and irrelevant to find the answer of the question.Now, with the helpf of the units, you can set this relation:gallons / year = (miles / year) / (miles / gallon) . . . .           [miles are canceled and the resultant quotient equals gallon / year]Substitute and compute:gallons / year = (12,000 miles / year) / (20 miles / gallon) =                                  = 600 gallons / yearHence, the answer is the third option 600 gallons / year.