A nurse requires a 40% alcohol solution. The nurse has 20% and 70% alcohol solutions on hand. How many liters of each should the nurse use to make 25 liters of the 40% solution?

Answer 1

amount of the 20% stuff --- x L
amount of the 70% stuff --- 25-x

.2x + .7(25-x) = .4(25)
how about multiplying each term by 10
2x + 7(25-x) = 4(25)
2x + 175 - 7x = 100
-5x = -75
x = 15

take over

Answer 2

Tasha needs 75 liters of a 40% solution of alcohol. She has a 20% solution and a 50% solution available. How many liters of the 20% solution and how many liters of the 50% solution should she mix to make the 40% solution?

Answer 3

Joseph would like to make 12 pounds of a coffee blend for $6.25 per pound. He blends Ground Chicory at $4.40 a pound with Jamaican Blue Mountain at $8.84 per pound. How much of each type of coffee should he use?