To determine the change in the amount of water in gallons in 1 minute, we can calculate the water removed per minute.
The pump removes 250 gallons of water in 5 minutes. So, we can find the rate of water removal per minute as follows:
\[ \text{Water removed per minute} = \frac{250 \text{ gallons}}{5 \text{ minutes}} = 50 \text{ gallons per minute} \]
Since the amount of water is decreasing, we denote the change as negative:
\[ \text{Change in amount of water in 1 minute} = -50 \text{ gallons} \]
So, the correct response is:
−50