Answer:
Caffeine remains in Doug’s system after 2 hours = 100.672 mg
Explanation:
Doug drank a soda with 130 mg of caffeine.
Caffeine drank = 130 mg
Each hour, the caffeine in the body diminishes by about 12%.
Reduction of caffeine per hour = 12 %
We need to find how much caffeine remains in Doug’s system after 2 hours.

Caffeine remains in Doug’s system after 2 hours = 100.672 mg