Question

If Niagara Falls eroded four feet over the last four years, how many feet does it erode each year?
Answer

0

1

4

sixteen

Answer 1

4 feet in 4 years is the same as:
\[\frac{4ft}{4yrs}\]When you reduce that you get:
\[\frac{1ft}{1yr}\]which is simple stating that it erodes at a rate of 1ft per year.