Goop Inc. needs to order a raw material to make a special polymer. The demand for the polymer is forecasted to be normally distributed with a mean of $250$ gallons and a standard deviation of $125$ gallons. Goop sells the polymer for $$25$ per gallon. Goop purchases raw material for $$10$ per gallon and Goop must spend $$5$ per gallon to dispose of unused raw material due to government regulations. $($One gallon of raw material yields one gallon of polymer.$)$ If demand is more than Goop can make, then Goop sells only what they made, and the rest of demand is lost. Suppose Goop purchases $300$ gallons of raw material. How many gallons of demand on average would remain unfulfilled?

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