SOLUTION: An 112 ounce mixture is created by combining two ethylene solutions. One solution is10% ethylene and the other is 2% ethylene. If the finale mixture is comprised of 7.9% ethylene s

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Question 939053: An 112 ounce mixture is created by combining two ethylene solutions. One solution is10% ethylene and the other is 2% ethylene. If the finale mixture is comprised of 7.9% ethylene solution, then how much of the 10% solution was used?
How do I do this? Thank you and please
Answer by mathmate(429) About Me  (Show Source):
You can put this solution on YOUR website!

Method 1: Using unknown x
step 1.
using unknown x=volume of 10% (=0.1) solution in ounces
then volume of 2% (=0.02) solution is 112-x ounces to make 112 ounces of 7.9% (0.079) solution.

step 2.
form the equation that mixes the two ingredients to make a 7.9% solution
0.1x+0.02(112-x) = 0.079(112)

step 3.
Solve for x
0.1x+2.24-0.02x = 8.848
0.08x=6.608
x=82.6
Volume of 2% solution = 112-82.6=29.4 ounces
Answer: 82.6 ounces of 10% solution, and 29.4 ounces of 2% solution.

method 2: using proportions
V(10%):V(2%)=(7.9-2) : (10-7.9)
=5.9 : 2.1
Volume of 10% solution = 112%285.9%2F%285.9%2B2.1%29%29=82.6 ounces
Volume of 2% solution = 112%282.1%2F%285.9%2B2.1%29%29=29.4 ounces
Answer: 82.6 ounces of 10% solution, and 29.4 ounces of 2% solution.