The population of a heard of cattle numbered was 5000 to begin with and was 10,000 after 10 years. If the population was growing exponentially, what was the growth rate? show all work
A) r=2
B) r=20
C)r=0.69
D)r=6.9




Respuesta :

Answer:

[tex]r=0.0718[/tex]. The closest value from your given choices is C)r=0.69

Step-by-step explanation:

To solve this we are using the standard exponential growth equation:

[tex]f(t)=A(1+r)^t[/tex]

where

[tex]f(t)[/tex] is the final population after [tex]t[/tex] years

[tex]A[/tex] is the initial population

[tex]r[/tex] is the growth rate in decimal form

[tex]t[/tex] is the time in years

We know from our problem that the initial population is 5000, the final population is 10000, and the time is 10 years, so [tex]A=5000[/tex], [tex]f(t)=10000[/tex], and [tex]t=10[/tex].

Let's replace the values and solve for [tex]r[/tex]:

[tex]f(t)=A(1+r)^t[/tex]

[tex]10000=5000(1+r)^{10}[/tex]

Divide both sides by 5000

[tex]\frac{10000}{5000} =(1+r)^{10}[/tex]

[tex]2=(1+r)^{10}[/tex]

Take root of 10 to both sides

[tex]\sqrt[10]{2} =\sqrt[10]{(1+r)^{10}}[/tex]

[tex]\sqrt[10]{2} =1+r[/tex]

Subtract 1 from both sides

[tex]\sqrt[10]{2}-1=r[/tex]

[tex]r=\sqrt[10]{2}-1[/tex]

[tex]r=1.0718-1[/tex]

[tex]r=0.0718[/tex]

We can conclude that the growth rate of our exponential equation is [tex]r=0.0718[/tex]. The closest value from your given choices is C)r=0.69