Determine the initial value and the rate of change in the following description. A 2,000-gallon tank is half full with 1,000 gallons of water. Water is being pumped into the tank at a rate of 15 gallons per minute.

The initial value is b=[ ], and the rate of change is m=[ ]
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The initial value is b=1000 gallons (the amount of water initially in the tank), and the rate of change is m=15 gallons per minute (the rate at which water is being pumped into the tank).