Using an exponential function, it is found that the decay rate is of 6.24% a year.
<h3>What is an exponential function?</h3>
A decaying exponential function is modeled by:

In which:
- A(0) is the initial value.
- r is the decay rate, as a decimal.
The half-life is of 10.75 years, hence A(10.75) = 0.5A(0) and this is used to find the decay rate r.



![\sqrt[10.75]{(1 - r)^{10.75}} = \sqrt[10.75]{0.5}](https://tex.z-dn.net/?f=%5Csqrt%5B10.75%5D%7B%281%20-%20r%29%5E%7B10.75%7D%7D%20%3D%20%5Csqrt%5B10.75%5D%7B0.5%7D)

1 - r = 0.9376.
r = 1 - 0.9376.
r = 0.0624.
The decay rate is of 6.24% a year.
More can be learned about exponential functions at brainly.com/question/25537936
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