Keiko's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee cost Keiko $4.15 per pound, and type B coffee costs $5.25 per pound. This month's blend used four times as many pounds of type B coffee as type A, for a total cost of $980.85. How many pounds of type A coffee were used?

39 pounds of type A coffee were used.

Step-by-step explanation:

Given: Cost of type A coffee is $4.15 per pound and cost of type B coffee is $5.25 per pound. Also, blend used four times as many pounds of type B coffee as type A.

To find: How many pounds of type A coffee were used.

Let be the number of pounds of type A coffee and be the number of pounds of type B coffee.

Then, according to question,

and

Substituting in , we get

⇒

⇒

⇒

⇒

Therefore, 39 pounds of type A coffee were used.

the graph in the attached figure

step-by-step explanation:

we have

using a graphing tool

the graph in the attached figure

the roots are ( x-intercepts) x=-0.5,x=1,x=3

the y-intercept is the point (0,3)