Question

A doctor prescribes 250 milligrams of a therapeutic drug that decays by about 10% each hour. Write an exponential model representing the amount A in milligrams of the drug remaining in the

patient's system after t hours.
A(t)=
Use the formula to find the amount of the drug that would remain in the patient's system after 3 hours. Round to the nearest milligram.
mg

Answer 1

A(3) = 185mg

Formula for exponential growth/decay is

A(t) = A0 * e^(xt)

Where A0 is your initial amount

x is your percentage

t is the time

A(3) = 250 * e^(-0.1*3)

A(3) = 185.2mg

Key point x is negative in this case as it's a decaying function. If it was growth it would be positive