Question

if a piece of sea floor has moved 50 km in 5 million years what is the yearly rate of sea-floor motion?

Answer 1

0.0001 km / year or 10^-5 km/year just take 50 km and divide it by 5 million

Answer 2

50 km = 50,000 meters

           (50,000 meters) / (5 million years)

       =    (5 x 10⁴) / (5 x 10⁶)    (meters/year)

       =           1 x 10⁻²      meter/year

       =           1 centimeter per year