can u help with this?

Question

A coffee merchant ha coffee beans that sell for $9 per pound and $12 per pound.The two types are to be mixed to create 100lb ofa mixture that will sell for $11.25 per pound. How mch of each type of bean should be used in the mixture?

Answer 1

OK, let's see. How about N for the number of pounds of beans that sell for $9/pound and T for the number of pounds of beans that sell for $12/pound.

We know that the total pounds of beans is 100, so N pounds + T pounds = 100 pounds

The mixture is supposed to sell for $11.25 per pound, so how can we write an equation for that? It's sort of a ratio or average. I guess N pounds times $9/pound plus T pounds times $12/pound would have to equal $11.25/pound x 100 pounds. As an equation, that is:
(N pounds x $9/pound) + (T pounds x $12/pound) = $11.25/pound x 100 pounds

Then you can solve for both equations by substituting 100 - T instead of N in the second equation, or you could substitute 100 - N for T in the second equation.

Answer 2

12 + 9 = 21

100 / 21 = 4.76

4.76