The volume of a cell is increasing at a rate of 100/(1 + t)2 m3/s, starting from

The volume of a cell is increasing at a rate of 100/(1 + t)2 μm3/s, starting from a size of 500 μm3.
Write pure-time differential equations to describe the above situations, find out what happens over the long term, and state whether the rule could be followed indefinitely.