Hydraulic engineers in the United States often use, as a units of volume of water, the ocre-foot, defined as the volume of water that will cover 1 acre (where 1 acre =43560ft2 ) of land to a depth of 1ft. A severe thunderstorm dumped 2.2in. of rain in 30min on a town of area 44km2. What volume of water, in acre-feet, fell on the town? Number Units