Question

A chemist mixes 100 milliliters of a solution that is 75% acid with 25 milliliters of a solution that is 35% acid. How many milliliters of acid are in the resulting mixture

Answer 1

well, how many mL of acid are in each to begin with? let's check for each

`\begin{array}c \cline{1-1} \textit{\textit{\LARGE a}\% of \textit{\LARGE b}}\\ \cline{1-1} \\ \left( \cfrac{\textit{\LARGE a}}{100} \right)\cdot \textit{\LARGE b} \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{75\% of 100}}{\left( \cfrac{75}{100} \right)100}\implies 75 ~~ \textit{mL of acid} \\\\\\ ~\hspace{11em}\stackrel{\textit{35\% of 25}}{\left( \cfrac{35}{100} \right)25}\implies 8.75 ~~ \textit{mL of acid} \\\\\\ ~\hspace{11em}75 + 8.75 \implies \text{\LARGE 83.75}`