Can you do Test 2 Section 3 #14? Thanks!

The thing to know here is that the basic form for exponential growth or decay is this:

When this question tells you that the substance decays at an annual rate of 13%, that means you have a growth rate of –0.13. The question also tells you that the starting amount is 325 grams and that the period in years is represented by .

We can plug the given information into the standard form:

Simplify the growth rate and you have your answer: