The rate of plate movement along the Mid Atlantic Ridge has been determined to be 3 centimeters per year At this rate how long will it take the Atlantic Ocean to widen another one kilometer?

What slowed down the spreading rate of the Ocean?  What is the average rate of tectonic plate movement?  Rate of plate movement along the mid atlantic ridge?  3 cmyr how long will it take the atlantic ocean to widen one kilometer?  13 How long did Charles Linbergs airplane flight across the Atlantic Ocean take?  If the mid-ocean ridge spreading center at the junction of the Pacific and Nazca plates is spreading at a rate of 15 cm yr how long will it take for new crust to reach the Peru Trench 4000 km away?  If the distance from the Mid Atlantic Ridge to the North Amiercan continent is 3000 km and new crust is generated at a rate of 3 cm yr-1 what is the age of the oldest Atlantic Ocean Crust?  What motion of the sea floor is responsible for the formation of the Mid-Atlantic Ridge's rift valley?  At the rate of 3 centimeters a year how many years would it take to widen by 1 kilometer?