Thread: Density

Vinaigrette salad dressing consists maily of oil and vinegar. The density of olive oil is 0.918 g/cm^3, the density of vinegar is 1.006 g/cm^3, and the two do not mix. If a certain mixture of olive oil and vinegar has a total mass of 397.8 g and a total volume of 422.8 cm^3, what is the volume of the oil and what is the volume of the vinegar in the mixture?

I'm sorry to bother anyone with this problem, but I have no clue how to work it. Please help.

These kind of problems used to give me fits, back in high school algebra class. They are not so hard once you get the hang of putting the word statement into equations. What you want to do is get two equations and two unknowns, then you can just use algebra.

All right, you know that the volume of vinegar plus the volume of oil is 422.8. You also know the mass of the vinegar plus the mass of the oil is 397.8. Thats two equations but four variables. Except you can change volumes to masses, or else masses to volume by (density =mass/volume) so then you can substitute and you will have two equations in two unknowns. Which you know how to solve, right?