now, the bacterium is doubling every minute.
that means, for every minute, it has a "rate of growth" of 100%, is just growing by 100% of whatever the current value is, or just doubling.
we also know that the initial value was just 1 bacterium, how many will there be in 42 minutes? namely at 11:42am.
[tex]\bf \qquad \textit{Amount for Exponential Growth}\\\\
A=I(1 + r)^t\qquad
\begin{cases}
A=\textit{accumulated amount}\\
I=\textit{initial amount}\to &1\\
r=rate\to 100\%\to \frac{100}{100}\to &1.00\\
t=\textit{elapsed time}\to &42\\
\end{cases}
\\\\\\
A=1(1+1.00)^{42}\implies A=1(2)^{42}\implies A=2^{42}[/tex]
