Let's say we'll mix "x" amount of the 80% solution, how much antifreeze is in it? well is just 80% of antifreeze, and the rest is something else.... what's 80% of "x"? so is (80/100)*x, or 0.8x.
likewise, the mixture will be a 70% solution, and let's say it adds up to "y" amount, so how much antifreeze is in it? well (70/100) * y or 0.7y.
so whatever "x" is, we know that x + 100 = y.
and we know that 0.8x + 10 = 0.7y.
likewise, the mixture will be a 70% solution, and let's say it adds up to "y" amount, so how much antifreeze is in it? well (70/100) * y or 0.7y.
so whatever "x" is, we know that x + 100 = y.
and we know that 0.8x + 10 = 0.7y.