SOLUTION: A 40% antifreeze solution and a 70% antifreeze solution is mixed to make 12 gallons of 50% antifrezze solution. How many gallons of each antifreeze solution should be used.

Question 158343: A 40% antifreeze solution and a 70% antifreeze solution is mixed to make 12 gallons of 50% antifrezze solution. How many gallons of each antifreeze solution should be used.
Found 2 solutions by jojo14344, atique.ah:
Answer by jojo14344(1512) (Show Source):
You can put this solution on YOUR website!
Let:
40% a/f =
70% a/f =
Number of gallons of + equals
------------------> eqn 1
We get, ----------> eqn 2
Also,
----> eqn 3
Substitute eqn 2 in eqn 3:

---->
----------------------> for the 40% a/f
In eqn 2:
----------------> for the 70% a/f
In doubt? go back eqn 3:

Thank you,
Jojo

Answer by atique.ah(23) (Show Source):
You can put this solution on YOUR website!
A 40% antifreeze solution and a 70% antifreeze solution is mixed to make 12 gallons of 50% antifrezze solution. How many gallons of each antifreeze solution should be used.
SOLUTION:
...............GALLONS....................%..........TOTAL
70% AF......... X........................0.7.........0.7X
40% AF..........Y........................0.4.........0.4Y
MIX 50%.....X+Y=12............0.5............0.5*12=6

0.7X+0.4Y=6 EQ 1
X+Y=12 EQ 2
Solve for y and x and get the answer