Christine is building a deck in her backyard. In order to place
the posts, she will make concrete using a mixture. The mix
requires 1 part water to 2 parts cement to 3 parts sand. The
relationship between water, cement, and sand is proportional. If
she has 25 pounds of cement and will use it all, how many
pounds of sand will she need? One gallon of water weighs
about 8.34 pounds. How many gallons of water will she need?
Round to the nearest tenth.