Let ER stand for U.K. pound/$ exchange rate (i.e., the number of U.K. pounds per U.S. dollar)

Question:

Let ER stand for U.K. pound/$ (i.e., the number of U.K. pounds per U.S. dollar) and RPR stand for the ratio of the U.S. CPI/U.K. CPI. Is the correlation between ER and RPR expected to be positive or negative? Why? Show your computations. Would your answer change if you found correlation between ER and (1/RPR)? Why?
For Information: Refer to Table 1-3 in Problem 1.7.
Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...