Question 1006468
Understanding the basic lesson will mean you understand all of these types:
<a href="http://www.algebra.com/my/Two-Part-Mixture-with-one-material-quantity-unknown.lesson?content_action=show_dev">Two-Part Percent Mixture with One Material Quantity Unknown</a>


The 70 liters of alcohol solution is 85% alcohol, but the <b>water is 0% alcohol</b>; so the quantity of the resulting solution changes, increases because of adding the water.