Is my answer correct?
Write an exponential function to model this situation: a population of 420 animals decreases at an annual rate of 21%. Then predict the value of the function after 5 years (to the nearest whole number).

My answer:
f(x) = 420(1.21)^x; 2541 animals

Question

Is my answer correct?
Write an exponential function to model this situation: a population of 420 animals decreases at an annual rate of 21%. Then predict the value of the function after 5 years (to the nearest whole number).

My answer:
f(x) = 420(1.21)^x; 2541 animals

anonymous · Answer

420(1.21)^5 = 2541

hero · Answer

The function is decreasing so that means that the value in parentheses would have to be between 0 and 1

anonymous · Answer

I misread the question, I thought it said it was increasing.

anonymous · Answer

Would it be,

f(x) = 420(0.79)x; 129 animals?

anonymous · Answer

$$P(t)=420\times (.79)^t$$
$$P(5)=420\times (.79)^5=129$$ rounded

anonymous · Answer

yes, 129