There are 1000 milliliters per liter, so...
750 ml x 1 liter/1000 ml =
750/1000 = .75 liters
They would be traveling at 47.5 mph
They do not appear to be symmectric. they seem to line up well
The easiest way is to do some simple division, where 500 is the distance & 20 is the duration.

The elevator is descending 25 ft/s.