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?  Choose the correct choice from the following answers:  A) 9  B) 14  C) 25  D) 30  E) 44
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 --&gt; capacity=140/0.8= 
<gadget id="calculator">140/0.8</gadget>
<output>175</output>
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: 44.
<result>E</result>
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?