A chemical company mixes pure water with their premium antif

A chemical company mixes pure water with their premium antifreeze solution to create an inexpensive antifreeze mixture. The premium antifreeze solution contains 70% pure antifreeze. The company wants to obtain 140 gallons of a mixture that contains 15% pure antifreeze. How many gallons of water and how many gallons of the premium antifreeze must be mixed?

Solution

final solution is 140 gallon of 15% antifreeze
volume of pure antifreeze = 15% of 140 gallon = 21 gallon

Let say we mix x gallon water and y gallon premium antifreeze
amount of pure antifreeze = 70% of y
70*y/100 = 21
y = 30 gallon

x+y = 140 gallon
x = 110 gallon

Answer:
water: 110 gallon
premium antifreeze : 30 gallon