Answer: 39 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 Lena $5.70 per pound, and type B coffee costs $4.25 per pound. The total cost of the mixture is $885.30. It means that
5.7x + 4.25y = 885.3- - - - - - - - - -1
This month's blend used four times as many pounds of type B coffee as type A. It means that
y = 4x
Substituting y = 4x into equation 1, it becomes
5.7x + 4.25 × 4x = 885.3
5.7x + 17x = 885.3
22.7x = 885.3
x = 885.3/22.7
x = 39
y = 4x = 4 × 39
y = 156
