Final answer:
About 200 million years ago, the continents of Africa and North America were adjacent during the Pangea era. Through plate tectonics, they've been separating at a rate of about 2.5 cm per year. Assume you're 15, then they've moved about 37.5 cm since you were born.
Step-by-step explanation:
Africa and North America were adjacent to each other about 200 million years ago, during the late Pangea era.
The mid-Atlantic Ridge continually pushes the two continents apart, and they have been separating at an average rate of 2.5 cm per year. Suppose you are 15 years old, then Africa and North America have moved roughly 37.5 cm apart since you were born.
In calculating these approximations, we are assuming that the rate of plate tectonics is constant, which is a simplification.
It's worth noting that rates can vary, and not all parts of the spreading seafloor spread at the same speed. The spreading rate is derived from past geological events and measurements, and thus, this assumption is made to facilitate our calculation.
Learn more about Plate Tectonics