Algebra: Chapter 10, Lesson 8, page 460.
Mixture Problems
Whether they are acid mixes or coffee bean blends or mixed nuts, we treat these problems the same. `x` will stand for the amount of one of the mixes and the (total amount – x) is the amount of the other mix. Convert percentages to decimals (remember `D2P`?) and use monetary cost per pound as decimals (like 2 dollars and 4 cents is equal to 2.04) and you’ll be fine.
The problems CAN be solved with 2 variables, `x` and `y`, BUT it requires 2 equations and substitution – I think it is just twice the work of developing one equation with just 1 variable. For these problems, the book and I agree on the easiest method!
Here is a great Purplemath link.