After a Baby Whale Is Born, Its Weight Gain at Any

True/False

After a baby whale is born, its weight gain at any time is proportional to the product of its weight and the difference between its weight and its weight at maturity. Give a differential equation satisfied by f(t), its weight at time t. Does the following accurately describe this situation?
$\begin{array} { l } y ^ { \prime } = k y ( M - y ) \\M = \text { weight at maturit } \\k > 0\end{array}$