# Relative growth rate problem

1. Oct 25, 2006

### bobbarkernar

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 90 cells.

the question asks to find the relative growth rate, if we measure t in hours.

im not exactly sure what they are asking for?
if someone can point me in the right direction.

2. Oct 25, 2006

### arildno

What does growth rate mean, and what does "relative growth rate" mean?

3. Oct 25, 2006

### bobbarkernar

well growth rate is that rate at which a certain population increases or decreases. so relative growth rate is the rate at which a population increases or decreases relative to time?

4. Oct 25, 2006

### arildno

No, "relative growth rate" means the growth rate relative to the SIZE OF THE POPULATION at the same time!

1. So, if the population at time t is x(t), what is its growth rate at time t?
2. And what is its relative growth rate?
3. What type of growth do you think the bacterium population experiences?
4. What type of function must x(t) be?
5. Use the info to determine x(t)!
6. Calculate the relative growth rate!