SOLUTION: This is a question I missed from a recent test. I'm beating my head against the wall trying to figure this out. Thanks in advance for any help you can provide. How much of a 7

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We want to end up with a 10 liters of 40% solution. That means that of the 10 liters, 4 liters are the chemical, and the rest is something else. To make this mixture, we want to mix x liters of 75% solution with enough 25% solution to make the full 10 liters. So the amount of 25% solution must be liters.

The 75% solution has liters of chemical, and the 25% solution has liters of chemical. These two quantities must add up to the 4 liters that make up the amount of chemical in the final solution (geez, that sounds ominous!).

So:








So there are 3 liters of 75% solution, meaning that there are 7 liters of 25% solution.

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