A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 60 cells. Find the relative growth rate.

Step-by-step explanation:

Given that,

Cells are divided into two cell every 20mins, this implies that the half-life is 20mins

Initial population growth is 60cells

Growth rate r?

Population growth is modeled as

P(t) = Po•exp(rt)

Where,

Po is the initial growth at t= 0

Po= 60

P(t) is population at any time t.

Since the population doubles every 20mins(⅓hr)

Then, P(⅓) = 2×60 =120

Then, P(t) = 120cells

So, applying the formula

P(t) = Po•exp(rt)

120 = 60•exp(⅓r)

120/60 = exp(r/3)

2 = exp(r/3)

Take In of both sides

In(2) = r/3

Cross multiply

r = 3In(2)

r = 2.079 /hour

The growth rate is 2.079/hour.