coffee shop

Question

A coffee shop plans to mix 90 pounds of coffee that sells for $12 per pound with coffee that sells for $5 per pound to get a mixture that will sell for $10 per pound. How many pounds of the $5 coffee should be used?

Answer 1

Let x = number of pounds of $5/lb coffee

 

Then, there are x+90 pounds of the mixture

 

Value of $12/lb coffee = 12(90) = 1080

Value of $5/lb coffee = 5x

Value of $10/lb coffee = 10(x+90)

 

Then, 1080 + 5x = 10(x+90)

 

         1080 + 5x = 10x + 900

 

                    5x = 180

 

                      x = 36 lb