A population of snails is located in a lake that has a carrying capacity of 20,000 snails. The intrinsic capacity for increase for these snails is 0.15 and the current population is 12,000. In a year, how big do you expect the snail population to be?

A. 13,800
B. 20,000
C. 12,720
D. 16,840

Respuesta :

Answer: C. 12,720

Step-by-step explanation:

In Logistic growth,  the change in population is given by :

[tex]\dfrac{dP}{dt}=rP\left(1-\dfrac{P}{C}\right)[/tex]   ...(*)

, where P= Initial population , t= time , r= intrinsic rate and [tex]\dfrac{dP}{dt}[/tex]=Change in population and C = Carrying capacity.

As per given , we have

P=12,000

r=0.15

C=20,000

t=1 year

Substitute all values in (*) , we get

[tex]\dfrac{dP}{dt}=(0.15)(12000)\left(1-\dfrac{12000}{20000}\right)\\\\=(1800)(0.4)\\=720[/tex]

Now, Total population of snails after a year = [tex]P+\dfrac{dP}{dt}=12,000+720=12,720[/tex]

Hence, the correct answer is C. 12,720 .