Elsa's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee costs Elsa $5.70 per pound, and type B coffee costs $4.30 per pound. This month's blend used twice as many pounds of type B coffee as type A, for a total cost of $300.30. How many pounds of type A coffee were used?

21 pounds of type A coffee were used.

Step-by-step explanation:

Let x represent the number of pounds of type A coffee that were used in the blend.

Let y represent the number of pounds of type B coffee that were used in the blend.

Type A coffee costs Elsa $5.70 per pound, and type B coffee costs $4.30 per pound. The mixture sold for a total cost of $300.30. It means that

5.7x + 4.3y = 300.3- - - - - - - - - - -1

This month's blend used twice as many pounds of type B coffee as type A. It means that

y = 2x

Substituting y = 2x into equation 1, it becomes

5.7x + 4.3 × 2x = 300.3

5.7x + 8.6x = 300.3

14.3x = 300.3

x = 300.3/14.3

x = 21