It is common for people to take a dosage of acetaminophen, a pain medication, once per day. The medicine works best when there is a specific amount in the bloodstream. A doctor found that the amount of acetaminophen, y, (in mg) remaining in a person's bloodstream x hours after taking a 1000 milligram dosage can be modeled by the equation:
y = 1000(0.76)^x
What does the number 0.76 in this model indicate about the amount of acetaminophen in the blood stream?
a. It decreases at a rate of 1000% per hour.
b. It decreases at a rate of 76% per hour.
c. It increases at a rate of 24% per hour.
d. It decreases at a rate of 24% per hour.