Hi,

You start with:

3cm/s * 60s/min ---- Seconds cancel and we're left with minutes

180cm/min * 60min/hr ---- Minutes cancel and we're left with hours

10,800cm/hr * 1ft/30.48cm ---- Centimeters cancel and we're left with feet

354.33ft/hr * 1M/5,280ft ---- Feet cancel and we're left with MPH

0.0671 MPH

So yes, you are correct!

I hope this helps.

-Nathan