Question

After a robot vacuum is fully charged, it can run for 15 minutes.
It can vacuum 1
2 square foot every second. Can a fully charged
robot clean a room that is 400 square feet without recharging?

Answer 1

Yes. 15 minutes = 900 seconds. At 1/2 square foot per second it cleans 900 × 1/2 = 450 sq ft, which is more than 400 sq ft (50 sq ft spare).