Answer:
57.9 milligrams
Explanation:
To solve this problem, we need to use an exponential decay equation. In this case, the equation will be: A(t) = A(0) * 0.72^t, where A(t) is the amount of antibiotic left after t hours, A(0) is the initial amount of antibiotic, and 0.72 is the constant rate of decay (since the body breaks down 28% of the antibiotic every hour). Plugging in our values, we get: A(7) = 380 * 0.72^7, which equals about 57.9 milligrams. So, after 7 hours, there