Question

Question 17

5 pts
The population of fish in an aquarium can be modeled after exponential growth. If there
were originally 3 fish and after 6 weeks there were 31 fish, how many fish would there
be after 14 weeks?
321 fish
698 fish
452 fish
815 fish

Answer 1

698 fishes

Explanation:

Generally, we can represent an exponential growth function as;

y = a•(1 + r)^t

originally, there were 3 fishes

The original value in this case means a = 3

After 6 weeks, there were 31

31 in this case is y

r is the increase percentage or rate

t is the time

So, we have it that;

31 = 3•(1 + r)^6

31/3 = (1 + r)^6

10.33 = (1 + r)^6

ln 10.33 = 6 ln (1 + r)

ln 10.33/6 = ln (1 + r)

e^0.3892 = (1 + r)

1 + r = 1.476

r = 1.476-1

r = 0.476 or 47.6%

So the growth percentage or rate is 47.6%

For 14 weeks, we simply have the value of t as 14;

So ;

y = 3•(1 + 0.476)^14

y = 3(1.476)^14

y = 698 fishes