



 
Hi Abdel, Suppose it pumps out $x$ gallons when it is working at 100%. When it is working at 70% it then pumps out $0.70 \times x.$ Thus you know that $0.70 \times x = 4500 \mbox{ gallons.}$ Solve for $x$. When it works at 85% it will put out $0.85 \times x \mbox{ gallons.}$ Penny  


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