SOLUTION: Raisins sell for $3.50 per pound, and granola sells for $5.90 per pound. Terri bought some raisins and some granola. The total weight was 2.1 pounds and cost $8.79. Let r repres

Algebra ->  Test -> SOLUTION: Raisins sell for $3.50 per pound, and granola sells for $5.90 per pound. Terri bought some raisins and some granola. The total weight was 2.1 pounds and cost $8.79. Let r repres      Log On


   

Question 788188: Raisins sell for $3.50 per pound, and granola sells for $5.90 per pound. Terri bought some raisins and some granola. The total weight was 2.1 pounds and cost $8.79.
Let r represent the number of pounds of raisins Terri purchased.

Which expression represents the number of pounds of granola she purchased?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
This is a mixture problem. The prices are like concentration in units dollars per pound.

r = how many raisins
g = how many granola
(both as pounds)

%283.50r%2B5.90g%29%2F2.1=8.79%2F2.1
But you do not need to show as concentration or cost per pound; you just need this:
highlight%283.5r%2B5.9g=8.79%29
You also need highlight%28r%2Bg=2.1%29

THE REST OF THE PROCESS:
You are asked for the pounds of raisins, so solve the system for r. First solve one equation for g, and substitute this expression for g in the other equation; and from this, solve for r.