To convert Maria's percentage to a fraction, we first rewrite the percentage as a fraction over 100. A percentage is essentially a fraction out of 100, after all.
So, with the 65% acid, we rewrite this as 65 / 100. This creates a fraction, but it's often useful to simplify fractions to their lowest, simplest terms.
To simplify a fraction, we look for a number that can divide both the numerator (top number) and the denominator (bottom number) evenly.
When we analyze 65 and 100, we discover that they share a common factor of 5. So we can divide both numbers by 5 to simplify the fraction. When we divide 65 by 5, we get 13, and when we divide 100 by 5, we get 20.
Therefore, the fraction in simplest form for Maria's 65% solution is 13/20.