namely, how many times 2/3 goes into 4, well, let's just divide them then
[tex]\bf \cfrac{\stackrel{\textit{total hours}}{4}}{\stackrel{\textit{hours per activity}}{\frac{2}{3}}}\implies \cfrac{\quad \frac{4}{1}\quad }{\frac{2}{3}}\implies \cfrac{4}{1}\cdot \cfrac{3}{2}\implies \cfrac{12}{2}\implies 6[/tex]
