Solving a percent mixture

Question

A chemical company mixes pure water with their premium antifreeze solution to create an inexpensive antifreeze mixture. The premium antifreeze solution contains
60%
pure antifreeze. The company wants to obtain
120
gallons of a mixture that contains
35%
pure antifreeze. How many gallons of water and how many gallons of the premium antifreeze solution must be mixed?

 

Answer 1

There are several approaches to this type of problem. The most common would probably be as follows:

Let x = gallons of premium (60%) antifreeze.  Water will be 0% antifreeze.

(x gal)(60%) + (120 - x gal)(0%) = (120 gal)(35%)

60 x = 4200

x = 70 gallons of premium 60% antifreeze + 50 gallons of water = 120 gallons 35% antifreeze