7. Inflation data of a foreign country for three years are as follows:

Index Change in Index Annual Rate of Inflation January 1, 2015 150 —

January 1, 2016 200 50 50 , 150 = 33%

January 1, 2017 250 50 50 , 200 = 25%

January 1, 2018 330 80 80 , 250 = 32%

The cumulative three-year inflation rate is:

a 45%

b 90%

c 120%

d 180%

496 CHAPTER 14 p R O B L E M S