Question

Caffeine is the active ingredient in coffee and many energy drinks. Once caffeine is consumed it

has a half-life in the body of approximately 4 hours. An average cup of coffee contains 100mg of
caffeine. Suppose you drink a cup of coffee at 8AM, followed by another cup at 10AM and an
afternoon cup of coffee at 3PM. How much caffeine is left in your body when you go to sleep at
11PM?

Answer 1

1 half-life = 4 hours

8 AM = 100 mg

(2 hours)

10 AM = 50 + 100 mg

(4 hours)

3 PM = 25 + 100 mg

(8 hours)

11 PM = --> 0 mg <--