Question

There are 3 grams of sodium in 1/2 of a liter of soda.how much is in 2/3 of a liter

Answer 1

$\bf \begin{array}{ccll} \stackrel{sodium}{grams}&\stackrel{soda}{liters}\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 3&\frac{1}{2}\\\\ g&\frac{2}{3} \end{array}\implies \cfrac{3}{g}=\cfrac{\quad \frac{1}{2}\quad }{\frac{2}{3}}\implies \cfrac{3}{g}=\cfrac{1}{2}\cdot \cfrac{3}{2}\implies \cfrac{3}{g}=\cfrac{3}{4} \\\\\\ 12=3g\implies \cfrac{12}{3}=g\implies 4=g$