Question 729631: How many liters each of 8%, 10%, and 20% hydrogen peroxide should be mixed together to get 8 liters of 12.5% solution, if the amount of 8% solution used must be 2 liters more than the amount of 20% solution used?
Found 3 solutions by lynnlo, ikleyn, josgarithmetic:
Answer by lynnlo(4176)   (Show Source):
Answer by ikleyn(53418)  (Show Source):
You can put this solution on YOUR website! .
How many liters each of 8%, 10%, and 20% hydrogen peroxide should be mixed together to get 8 liters
of 12.5% solution, if the amount of 8% solution used must be 2 liters more than the amount of 20% solution used?
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Ingredients: x liters of the 20% hydrogen peroxide;
(x+2) liters of the 8% hydrogen peroxide;
and (8 - x - (x+2)) = 6-2x liters of the 10% hydrogen peroxide.
Write equation for the content of hydrogen peroxide
0.2*x + 0.08*(x+2) + 0.1*(6-2x) = 0.125*8.
Simplify and find x
0.2x + 0.08x + 0.16 + 0.6 - 0.2x = 1,
0.2x + 0.08x - 0.2x = 1 - 0.16 - 0.6
0.08x = 0.24
x = 0.24/0.08 = 3.
ANSWER. Use 3 liters of the 20% hydrogen solution PLUS 3+2 = 5 liters of the 8% hydrogen solution
and do not use the 10% hydrogen solution, at all.
CHECK. The final concentration will be (0.2*3 + 0.08*5)/8 = 1/8 = 0.125 = 12.5%, correct.
Solved.
Answer by josgarithmetic(39701) (Show Source):
You can put this solution on YOUR website!
Concentration, % Volume, liters pure hydrogen peroxide
8 v+2 0.08(v+2)
10 8-(v+2)-v=6-2v 0.1(6-2v)
20 v 0.2v
TOTAL 12.5 8
 , to represent the final concentration.
Simplify and solve....
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