6.3 In March 1991, the U.S. dollar was worth 137 yen. In October 2000, the rate was 108 yen.

A. What is X0 (1991)? What is X1 (2000)?

B. What is E0 (1991)? What is E1 (2000)?

C. What was the percentage devaluation or revaluation of the yen in terms of the U.S. dollar?

D. What was the percentage devaluation or revaluation of the dollar in terms of the yen?