Answer:
The correct answer 7.5 hours.
Explanation:
In this case, half life refers to the time that is necessary for a quantity to reduce to half of its original value. In this case, the half-life of caffeine is 5.7 hours, meaning that if we had 10 ounces of it, the remaining after this time would be 5 ounces.
In the question, the initial amount is 16 ounces, so it will take 7.5 hours of the caffeine to remain in his body.