Answer:
32 lb
Step-by-step explanation:
Let a = number of pounds of type A coffee used.
Let b = number of pounds of type B coffee used.
From the statement:
"This month's blend used three times as many pounds of type B coffee as type A"
we get this equation:
b = 3a
"Type A coffee costs Karen $5.50 per pound, and type B coffee costs $4.25 per pound."
She spend (in dollars) 5.50a + 4.25b, but since b = 3a, we get
5.5a + 4.25(3a) = 5.5a + 12.75a.
She spent $584, so
5.5a + 12.75a = 584
18.25a = 584
a = 32
She used 32 lb of type A coffee.