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 =