Question

An empty aquarium has 5.00 kg of water added each second, and

2.50% of the total water removed each second.

17.

Determine by hand what the mass will be when the aquarium

reaches equilibrium.

Answer 1

The mass of water in the aquarium is:

$$m=5t-0.025mt$$

The equilibrium means the moment when the water removed equals water added:

$$5t=0.025mt,\\ 5=0.025m,\\ m=200\text{ kg}.$$