Answer:
36 gallons of each first brand and 24 gallons second brand of antifreeze must be used.
Explanation:
Let the volume of two different antifreeze be x and y.
Total volume required = 60 gal
x + y = 60 gal ...(1)
In order to obtain 60 gallons of a mixture that contains 45% pure antifreeze.
[tex]x\times 35\%+y\times 60\%=60 gal\times 45\%[/tex]
[tex]35x+60 y=2700 gal[/tex]
[tex]7x+12y=540 gal[/tex]
On solving equation (1) ans (2), we get:
x = 36 gal, y = 24 gal
36 gallons of each first brand and 24 gallons second brand of antifreeze must be used.