Word problem

Question

A chemical company makes two brands of antifreeze. First brand is 60% pure antifreeze the second brand is 85% antifreeze. In order to obtain 80 gallons of mixture that contains 80% pure antifreeze, how many gallons of each brand of antifreeze must be used ? 

Answer 1

If we use x gallons of 60% antifreeze then we use 80-x gallons of 85% antifreeze

 

The amount of antifreeze in the 60% is .6x

The amount of antifreeze in the 85% is .85(80-x)

 

.6x + .85(80-x) = .8(80)

.6x + 68 - .85x = 64

 

Finish solving for x to obtain the gallons of 60% antifreeze used.

Then 80-x will be the amount of 85% antifreeze used.