Acoffee merchant has two types of coffee beans, one selling for $9 per pound and the other for $15 per pound. the beans are to be mixed to provide 100 lb of a mixture selling for $13.50 per pound. how much of each type of coffee bean should be used to form 100 lb of the mixture?

To form 100 lb of the mixture we need 25 lbs of $9 coffee beans and 75 lbs of $15 coffee beans.

Step-by-step explanation:

Let x be the number of pounds of $9 coffee beans and y be the number of pounds of $15 coffee beans.

We know that the mixture must weigh 100 lb

and the total cost per pound is given by

Now, we can solve the system of equations

Isolate x for

Substitute into the second equation

Isolate y

For substitute y = 75

To form 100 lb of the mixture we need 25 lbs of $9 coffee beans and 75 lbs of $15 coffee beans.

positive

step-by-step explanation:

the quadrant is facing upwards