How long is 4.2 miles by walking?

Answer 1

4.2 miles walking is 4.2 miles long., but

if you look up "how fast does a human walk" you can do the math to get how long it will take to walk 4.2 miles:

4.2mi/2.5mph=1.68 hrs or 100.8 mins

ballpark, depending on how fast you walk. see the provided link.

Answer 2

4.2 miles into kilometers