8
Question How many times can a person circumnavigate (go around the world) the Earth in their lifetime, if they walk non-stop? Consider the distance around the Earth as 40,000 km. (Page 35)
Assumptions Circumference of Earth = 40,000 km Average walking speed = 5 km/hr Maximum walking hours per day = 8 hours (approx.) years spent walking. Let’s assume an active span of 60 years (ages 15 to 75) Distance covered in 1 day = 8 × 5 = 40 km Total days walked over = 60 × 365 = 21,900 days Total lifetime distance walked = 21900 × 40 = 876000 km Earth circumnavigations = 876000 + 40,000 = 21.9 times Linear Growth Vs Exponential Growth