Posted by Carla on .
Find the CPI for each year(2005 is he base year;and take 2005 as the fixed basket of goods for each year):
2005 price of apple is $1 for 100 quantity produced. Banana $2 for 50 quantity produced.
2006 price of apple is $2 for 150 quantity produced. Banana $3 for quantity of 100.

economics 
economyst,
First calculate the "weight" of each good  that is the percentage of total expenditures spent on that good. In 2005, $100 are spent on apples, $100 on bananas, for a total of $200. The weight of apples is 0.50
In 2006, price of apples went up by 100%, price of bananas went up by 50%
Take the weighted average .5*100% + .5%50% = 75%
CPI in 2005 = 100, CPI in 2006 = 175.