One tank is filling at the rate of 3/4 gallon / 2/3 minute a second tank is filling at the rate of 3/8 gallon per 1/2 minute which tank is filling faster equation
[tex]\bf \cfrac{3}{4}\cdot \cfrac{2}{2}\implies \cfrac{6}{8}\quad \textit{clearly then }\cfrac{9}{8}\textit{ is larger than }\cfrac{6}{8}
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\stackrel{\stackrel{tank's~volume}{gallons}}{y}=\cfrac{9}{8}\stackrel{minutes}{x}[/tex]