A chemical company makes two brands of antifreeze. The first brand is 45% pure antifreeze and the second brand is 70% pure antifreeze. In order to obtain 150 gallons of a mixture that contains 55% pure antifreeze, how many gallons of each brand of antifreeze must be used?

60 gallons of 70% antifreeze

Step-by-step explanation:

Let n be the amount of 70% antifreeze. And the second brand was 45% pure anti freeze Then:

According to the question

0.7 n+.45 (150-n) = 0.55 (150)

0.7 n+67.5-0.45 n=82.5

0.25*n=15

n=15/.25 = 60

You need 60 gallons of 70% antifreeze, and 90 gallons of 45% antifreeze for this mixture