199k views
4 votes
Soon after taking an aspirin, a patient has absorbed 320 mg of the drug. after 3 hours, only 40 mg remain. find an exponential model for the amount of aspirin in the bloodstream after t hours

User Jeremiah N
by
8.2k points

1 Answer

7 votes
The equation will be of the form:

A(t)= A_(0) e^(rt)
where A is the amount after t hours, and r is the decay constant.
To find the value of r, we plug the given values into the equation, giving:

40=320e^(3r)
Rearranging and taking natural logs of both sides, we get:

ln\ 0.125=3r

r=(ln\ 0.125)/(3)=-0.693
The required model is:

A=A _(0) e^(-0.693t)
User Jwi
by
8.4k points