a rainstorm increased the amount of water stored in state j reservoirs from 160 billion gallons to 200 billion gallons . if the storm increased the amount of water in the reservoirs to 50 percent of total capacity , approximately how many billion gallons of water were the reservoirs short of total capacity prior to the storm ?
"let total capacity be x we know 200 = 0.50 x x = 200 / 0.50 = 400 prior to storm , we had 160 bn gallons 400 - 160 = 240 answer : a"
divide(divide(multiply(200, const_100), 50), const_2)