Question

Rachel counted all the earthworms in a square meter in her back yard and found she had 36. She went back a week later and found she had only 30. Rachel knew that this was far too few to maintain her lawn so she decided to study the population for a couple of weeks. She found there were 9 worms born per week and 5 died per week. She also found 10 left for a nearby plot of land and 8 worms came from nearby plots during that week. Was the population growing or shrinking? What was the growth rate of the population? Give your answer in worms per week. If she returns 2 weeks after she had 30 worms, what will the worm population be?

Answer 1

The population of earthworms in Rachel's backyard is shrinking. The growth rate of the population is 2 worms per week. If Rachel returns 2 weeks after she had 30 worms, the worm population will be 34 worms.

Step-by-step explanation:

The population of earthworms in Rachel's backyard is shrinking. To determine the growth rate of the population, we need to subtract the death rate from the birth rate. In this case, there are 9 worms born per week and 5 worms die per week. Additionally, 10 worms left for a nearby plot of land and 8 worms came from nearby plots. Therefore, the growth rate of the population is (9 + 8) - (5 + 10) = 2 worms per week.

If Rachel returns 2 weeks after she had 30 worms, the worm population will be 30 + (2 * 2) = 34 worms.