We know that the equation for density is:
[tex] D=\frac{m}{V} [/tex]
where D is the density, m is the mass in grams, and V is the volume.
Given two of the variables, we can then solve for density:
[tex] D=\frac{1250g}{1500mL}=\frac{0.833g}{mL} [/tex]
Therefore, we now know that the density of the gasoline is 0.833g/mL.