Question

You are driving in a foreign country, and you see a sign showing a speed limit of 60 km/h. What is that speed in miles per hour?

Answer 1

Answer:

1 m * 39.37 in/m / 12 in/ft = 3.281 ft

1000 m / km * 3.281 ft/m = 3281 ft/km

1 h * 3600 sec / hr= 3600 sec/hr

60 km/hr * 3281 ft/km / 3600 sec/hr = 54.68 ft/sec

Since 60 mph = 88 ft/sec   (a handy conversion factor)

V = 54.68 ft/sec  / 88 ft/sec * 60 mph = 37.3 mph

Or more simply

1 km = .621 mi  and 60 km/hr * .621 mi /km = 37.3 mph