I thought that too until I made up a simple example and worked through the numbers. Lets say you have a 100 ft non-walkway 400 ft walkway you walk at 10 ft/s

I thought that too until I made up a simple example and worked through the numbers. Lets say you have a 100 ft non-walkway 400 ft walkway you walk at 10 ft/s and the walkway moves at 10ft/s it takes 10 s to tie your shoes. Case 1 tie your shoes 10s walk 100ft 10s walkway 400 ft (400/(10+10)) 20s Total 40s Case 2 Walk 100 ft 10s Tie shoes on walkway 10s (in which time you travel 100ft) Rest of Walkway 300/(10+10) 15s Total 35s