Answer: Two-third of the jar is filled with flour.
Step-by-step explanation: Given that a jar can hold [tex]\dfrac{3}{4}[/tex] of a pound of flour and Austin empties [tex]\dfrac{1}{2}[/tex] of a pound of flour into the jar.
We are to find the fraction of the jar that is filled.
The quantity of the flour that the jar can hold is given by
[tex]Q_j=\dfrac{3}{4}~\textup{pound},[/tex]
and the quantity of the flour that is emptied by Austin into the jar is given by
[tex]Q_e=\dfrac{1}{2}~\textup{pound}.[/tex]
Therefore, the fraction of the jar that is filled will be
[tex]F=\dfrac{Q_e}{Q_j}=\dfrac{\dfrac{1}{2}}{\dfrac{3}{4}}=\dfrac{1}{2}\times\dfrac{4}{3}=\dfrac{2}{3}.[/tex]
Thus, two-third of the jar is filled with flour.