The density of gasoline at room temperature is 0.70 gmL If the gas tank of a car holds 13.0 gallons 49.2 L what is the mass of a tankful of gasoline?

First off, the density you're meaning must be .70 g/mL.

Multiply that by 1000 to get grams per liter (700), then multiply that by the volume (49.2 L).

34440g or 34.44kg or 75.93 pounds.