Answer: Sylvia should use 35 pounds of Kona coffee and 65 pounds of Columbian coffee
Step-by-step explanation:
Let x represent the number of pounds of Kona coffee that Sylvia should use.
Let y represent the number of pounds of Columbian coffee that Sylvia should use.
Sylvia wants to mix 100 pounds of Breakfast Blend coffee. This means that
x + y = 100
She is using two types of coffee to create the mixture. Kona coffee sells for $51 per pound and Columbian coffee sells for $11 per pound and the mixture would sell for $25 per pound.
This means that
51x + 11y = 2500 - - - - - - - - 1
Substituting x = 100 - y into equation 1, it becomes
51(100 - y) + 11y = 2500
5100 - 51y + 11y = 2500
- 51y + 11y = 2500 - 5100
- 40y = - 2600
y = - 2600/-40
y = 65
x = 100 - y
x = 100 - 65 = 35