Official Explanation
First, change to a percent by setting it equal to Multiply the top and bottom of the left fraction by 4, to get \(x = 12,\) i.e., 12%, which can also be obtained by cross-multiplying or by simply typing 3 ÷ 25 on the calculator and converting .12 to 12%. Then the pool went from 12% full at 12:00 to 28% full at 2:30. The increase is 28% - 12% = 16% of the pool’s full volume in 2.5 hours.
During this time, the pool was filled at a rate of 2 gallons per minute. We must convert 2.5 hours into 2.5 × 60 = 150 minutes, in order to find that gallons. This means that 300 gallons were added and that 300 gallons represents 16% of the pool’s total volume, say T. Then 300 = .16 T. Divide both sides by .16, and T equals 300 ÷ .16 = 1875, (A).
Answer: A