The Consumer Price Index for Planet Econ Consists of Only

The consumer price index for Planet Econ consists of only two items: books and hamburgers. In 2015, the base year, the typical consumer purchased 10 books for $25 each and 25 hamburgers for $2 each. In 2017, the typical consumer purchased 15 books for $30 each and 30 hamburgers for $3 each. The consumer price index for 2017 on Planet Econ equals:

A) 1.00
B) 1.15
C) 1.25
D) 1.45