Answer:
Remember, 1 is the multiplicative identity. That means that we can multiply a value by 1 and not change the value, only change the units.
For example: If we have 3 dozen eggs, how many eggs do we have?
3 dozen
(3 dozen)*(12 eggs / 1 dozen) = 36 eggs (dozen cancels out, leaving only eggs)
In this problem:
(16 miles / 1 week)
(16 miles / 1 week)*(52 weeks / 1 year) (weeks cancel out, leaving miles/year)
832 miles/year
Note: with either 365 (or 366) days in a year, there are 365/7 = 52.14 weeks in a year, but we'll use 52 because the problem gave miles/week.
Explanation: