Solution

The variables needed for this problem are:

**-** number of cups in the past week (number of cups per day × 7)

- percent of the U.S population that drinks coffee

Assuming 3 * 10^ 8 people in the US, we can assume that children and adults that do not drink coffee stand at about 40%

It is reasonable to assume that in the remaining 60% population**. **half drink 2 cups per day, a quarter drink 4 cups per day, and a quarter drink 1 cup per day.

Or, we have 2 × 0.5 + 4 × 0.25 + 1 × 0.25 = 2.25 cups per coffee drinker per day.

Or, 60% × 2.25 × 300,000,000 = 405 million cups each day

405 million cups × 7 days per week = **2.84 billion cups **per week

This estimate is very close to the actual number of __400 million__ cups per day.