Caffeine takes a certain amount of time to work through your system. One study some years ago showed that the half-life of caffeine in healthy adults is 5.7 hours (see source: Half Life of Caffeine). This means if you consume 200 mg of caffeine at mid-day, you would still have 100 mg in you at around 5:45 pm.
a) One fluid ounce of espresso has 64 mg of caffeine.
If Daniel drank an espresso at 8:00 am, when will he have 32 mg of caffeine in his system?
How many mg of caffeine will he have in his system at noon?
How many mg of caffeine will he have in his system at 8:00 pm?
How many mg of caffeine will he have in his system at 2 am the next morning?
b) Find an algebraic equation for the amount of caffeine in your system at any given time.