Answer:
The last option is correct: -4.3%
Explanation:
Continuous Exponential Growth or Decay
The exponential e is used when modeling continuous growth or decay that occurs naturally such as populations, bacteria, radioactive decay, etc.
If a quantity grows or decays continuously by a fixed percent, the pattern can be described by the function:
![P(t)=P_o e^(kt)](https://img.qammunity.org/2021/formulas/mathematics/high-school/1i0q1cx2hkzoa3o3hs5ab67wkiyas46nuq.png)
Where P(t) is the value at the time t
k is the continuous growth/decay rate. If positive is for growth if negative is for decay.
The given function is:
![P(t)=640 e^(-0.043t)](https://img.qammunity.org/2021/formulas/mathematics/high-school/kr3xq26jsx6mjnlzg1caizs3mgh2whhawf.png)
It can be seen the value of k is:
k = -0.043
Or, expressed as a percentage:
k = -4.3%
The last option is correct: -4.3%