Difficult# Bacteria Growth

APCALC-XMM4R8

The growth of a bacterial culture is modeled by the logistics equation:

$$y=\frac { 40 }{ 1+39{ e }^{ -1.14t } } $$

...where $y$ represents the number of grams of bacteria present after time $t$ hours.

At what time is the amount of bacteria increasing most rapidly?