



 
Angela, The conversion fact you need is that there are 231 cubic inches in a US gallon and hence I would start by converting the dimensions from feet to inches. The tank is 80 × 12 = 960 inches long and 30 × 12 = 360 inches long. If this results in a rise of r inches what is the volume of this rectangular layer of new water being added. Set this equal to 231 × 100,000 = 23,100,000 cubic inches and solve for r. Penny  


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