Answer:
the annual rate of inflation r is 0.023
Explanation:
Given by the expression:

The average price of a gallon of milk increased from $0.36 in 1913 to $3.53 in 2013.
Let


n = 2013 - 1913 = 100
replacing our values into the given equation; then the annual rate of inflation r is as follows:

r = 0.023
Hence, the annual rate of inflation r is 0.023