Question

Charmaine's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee costs Charmaine $4.10 per pound, and type B coffee costs $5.70 per pound. This month's blend used twice as many pounds of type B coffee as type A, for a total cost of $465.00 . How many pounds of type A coffee were used?

Answer 1

Type A cost=4.10=a
Type B cost=5.70=b

twice as many B as A, an unknown "n" amount of times equal 465$
(2*b+a)*n=465

insert the a/b prices:
(2*5.70+4.10)*n=465
n=465/(11.40+4.10)
n=465/15.50
n=30

so 30 pounds type A and 30*2=60 pounds type B were used