Question

A barrel holds 750 pounds of gasoline. The same barrel holds 1100 pounds of water when full. What is the density of gasoline? [Hint : when volume is constant, d ~ m]

Answer 1

When the volume is constant, density is proportional to mass: d ~ m.
Set up a
proportion:

750 pounds of gasoline - x
1100 pounds of water - 1
g/cm^3

Then from the proportion we can get the unknown value x:
x =
(750 * 1) / 1100 = 0.6818 g/cm^3
Thus, the density of gasoline is 0.6818 gram
per cubic centimeter.