A child with an ear infection is given a 200-mg ampicillin tablet once every four hours. About 12% of the drug in the body at the start of a four-hour period is still there at the end of that period. Calculate the quantity of ampicillin in the body right after taking the third tablet is given. If we keep on giving tablets to the child forever, what level of the drug in the body do we converge to? Explain.