At this rate, how long would it take for two continents 3100 kilometers apart to...

[micheal j]

...collide? Typical motions of one plate relative to another are 1 centimeter per year.

Express your answer in scientific notation..

I really need help!!!

 

[jimschem]

Your question boils down to how many centimeters are in 3100 km?
1 km = 1000 m
1 m = 100 cm

1 km = 1000 * 100 = 100,000 cm

3100 km = 3100 * 100000 = 310,000,000 cm or years

 

[Unregistered]

3.50×108 {\rm years}