[echonet]

Here's what I have to solve, easy right?:

"A full barrel holds 750 pounds of gasoline. The same barrel holds 1100 pounds of water when full. What is the density of the gasoline?"

I've go 2 problems with this:
  1. The density of water varies with temperature, right? Do you see any temperature
   anywhere in that question?

  2. The units are strange (pounds). Are there different densities for pounds?

I've done it without worrying about these things (using .99 for density and ignoring the unit conversions that I might need completely), and I got .68. Is this even near right?

Thanks a lot in advance for your help, don't worry this is not for homework!

[AWK]

Pounds are units of mass but not a density.
http://en.wikipedia.org/wiki/Density

[Padfoot]

From the relative difference between the 2 masses you can work out the density of gasoline using density of water=1gmL^-1.

Density water/Density gasoline=m(water)/m(gasoline)
(Since volume is constant)

Density gasoline=m(gasoline)/m(water)*Density water

[Borek]

Ignore temperature, assume water density is 1 g/mL. In genmeral you are right that the question should state in what temperature it all happens. But for all practical purposes water is 1.0 g/mL regardless of temp.