[tex]\bf \begin{array}{ccll} tons&weeks\\ \cline{1-2}\\ \frac{3}{4}&1\frac{1}{2}\\\\ 2&x \end{array}\implies \cfrac{~~\frac{3}{4}~~}{2}=\cfrac{~~1\frac{1}{2}~~}{x}\implies \cfrac{~~\frac{3}{4}~~}{2}=\cfrac{~~\frac{3}{2}~~}{x}\implies \cfrac{~~\frac{3}{4}~~}{\frac{2}{1}}=\cfrac{~~\frac{3}{2}~~}{\frac{x}{1}} \\\\\\ \cfrac{3}{4}\cdot \cfrac{1}{2}=\cfrac{3}{2}\cdot \cfrac{1}{x}\implies \cfrac{3}{8}=\cfrac{3}{2x}\implies 6x=24\implies x=\cfrac{24}{6}\implies x=4[/tex]