To answer this question, you need to know how to convert milliliters into liter then into a gallon. In this question, you are given the gasoline density (0.737g/ml) and the volume (12.8gallon). The information is enough to determine the gas weight. The calculation would be:
Gas weight= density * volume
Gas weight= 0.737g/ml * 12.8 gal * 3.78L/gal * 1000ml/L= 35659.008 grams