If an initial quantity
continuous grows at an exponential rate
, then the final amount
after a time
is given by the following formula
.
A certain bacterium used to treat oil spills has a doubling time of
minutes.
A colony begins with a population of one bacterium
.
Since bacterium used to treat oil spills has a doubling
.
Substitute
in
we get
.
Substitute
, and
in
.

Apply logarithm on each side.
\
.
(a)
\Find modeling equation for exponential growth.
\Substitute
in
.
.
Modeling equation for exponential growth
.
(b)
\Find how many bacteria will be present after
minutes.
Substitute
,
and
in
.

.
Number of bacteria will be present after
minutes is
.
(c)
\Find how long it will take for the colony to grow
bacteria.
Since a population of
bacteria is sufficient to clean a small oil spill
.
substitute
,
and
in
.

Apply logarithm on each side.
\


Time taken for the colony to grow
bacteria is
minutes.
(a) Modeling equation for exponential growth
.
(b) Number of bacteria will be present after
minutes is
.
(c) Time taken for the colony to grow
bacteria is
minutes.