Ballpark — August 11, 2026

Answers to that day's 5 daily estimation questions.

Average speed of an Olympic sprinter (Usain Bolt)

27 mph

Peak speed during a 100m dash.

Percentage of Americans who have never left the US

~25%

Many others have only traveled to one or two countries.

Total length of the Great Wall of China

13,175 miles

The main line is shorter; this includes all branches.

Hearts in an octopus

3 hearts

Two pump blood to the gills; one to the rest of the body.

Stomachs a cow has

4 stomachs

Rumen, reticulum, omasum, and abomasum.