Illustrative model: a tank receives 7 liters per minute and loses 5. Inflow is reduced to 6 while outflow remains 5. What happens to the water stock?

Answer & explanation

It still rises, but more slowly.

The new net inflow is 6 minus 5, or 1 liter per minute. A smaller inflow reduces the growth rate but does not reverse it while inflow still exceeds outflow. The question assumes the stated rates remain constant.