Dear student,
Consumer Price Index reflects the change in the cost of living in two different situations. It shows the changes in the price level of specified basket of goods and services consumed by the households.
Consumer price index = Σ p1q0 / Σp0q0 * 100
where, p1q0 is total expenditure at current year prices and Σp0q0 is total expenditure at the base year prices/
Regards