SOLUTION: A chemical company makes two brands of antifreeze. The first brand is 30% pure antifreeze, and the second brand is 60% pure antifreeze. In order to obtain 90 gallons of a mixture t

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons  -> Linear Equations Lesson -> SOLUTION: A chemical company makes two brands of antifreeze. The first brand is 30% pure antifreeze, and the second brand is 60% pure antifreeze. In order to obtain 90 gallons of a mixture t      Log On


   

Question 1179771: A chemical company makes two brands of antifreeze. The first brand is 30% pure antifreeze, and the second brand is 60% pure antifreeze. In order to obtain 90 gallons of a mixture that contains 55% pure antifreeze, how many gallons of each brand of antifreeze must be used?
Found 2 solutions by ewatrrr, josgarithmetic:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
.30(90-x) + .60x = .55(90)
               x = .25(90)/.30 = 75gal 60%  and 15gal 30%

  4.5 + 45 = 49.5  checks.
Wish You the Best in your Studies.


Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Mixing 30% and 60% antifreezes
to make 90 gallons of 55% antifreeze

v gallons of the 60% antifreeze
60v%2B30%2890-v%29=55%2A90
-
6v%2B3%2890-v%29=55%2A9
6v-3v%2B3%2A90=55%2A9
2v-v%2B90=55%2A3
v=55%2A3-90
highlight%28v=75%29------gallons of the 60%
-
highlight%2815%29------gallons of the 30%