Question

Elizabeth is a nurse, and she just administered 1.8 milliliters of medication to one of her patients. Elizabeth knows that the amount of medication remaining in the patient's body will decrease by
1
3
each hour.
Write an exponential equation in the form y=a(b)x that can model the amount of medication, y, remaining in the patient's body after x hours.
Use whole numbers, decimals, or simplified fractions for the values of a and b.
y =

Answer 1

y = 1.8(2/3)^x

(Initial amount a = 1.8 mL; each hour the amount is multiplied by 1 − 1/3 = 2/3.)