a rainstorm increased the amount of water stored in state j reservoirs from 124 billion gallons to 138 billion gallons . if the storm increased the amount of water in the reservoirs to 82 percent of total capacity , approximately how many billion gallons of water were the reservoirs short of total capacity prior to the storm ?
"since we need to find only an approximate value and the answer choices are quite widespread , then use : 80 % instead of 82 % ( notice that this approximation gives the bigger tank capacity ) ; 140 billion gallons instead of 138 billion gallons ( notice that this approximation also gives the bigger tank capacity ) ; 130 billion gallons instead of 124 billion gallons ; . notice that the third approximation balances the first two a little bit . so , we ' ll have that : capacity ∗ 0.8 = 140 - - > capacity = 140 / 0.8 = 175 hence , the amount of water the reservoirs were short of total capacity prior to the storm was approximately 175 − 130 = 45 billion gallons . answer : e ."
divide(divide(multiply(138, const_100), 82), const_2)