8th Grade Performance Task
Contributed by: New Standards

Gina sees this sign on a track:
1.6 kilometers per mile
Then Gina finds a closer approximation of the same rate in a book:
1.61 kilometers per mile.
Gina converts a certain number of miles to kilometers. First she converts using
1.6 kilometers per mile, then she tries it using 1.61 kilometers per mile.
Her two answers are different-by exactly one kilometer!

What is the number of miles Gina converted? Show or explain how you know.