Using an exponential function, it is found that the mass of the radioactive sample at the beginning of the 13th day of the experiment was of 169.1 mg.
<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.
At the beginning of the first day of the experiment the mass of the substance was 500 grams and mass was decreasing by 8% per day, hence A(0) = 500, r = 0.08, and the equation is given by:
At the 13th day, the mass is given by:
More can be learned about exponential functions at brainly.com/question/25537936