Question

Peggy has been studying a type of bacteria that triples every month. Originally, there were 2 bacterial cells. She wants to know how many there will be after 24 months. Which equation should she use?

Answer 1

Let $u_n$ represent the number of bacteria after n months.

$u_0=2$ is the original number of bacteria

$u_1=2*3=6$

$u_2=2*3*3$

$u_3=2*3*3*3$

so it is clear that :

$u_n=2* 3^{n}$

After 24 months, there will be $u_2_4=2* 3^{24}$ many bacteria.


Answer: 

the equation:
$u_n=2* 3^{n}$, where u_n is the number of bacteria after n months,

$u_2_4=2* 3^{24}$