How can CPI or GDP deflator be used to compare two nominal figures from two different time periods? Example: You could buy a movie ticket for a quarter back in 1935 . Today the price of a movie ticket at the AMC theaters is around $15. In fact, I paid $16 to see Top Gun 2 last month. That was a good movie! How can you use CPI or the GDP deflator to compare the nominal price of a movie ticket in 1935 and in 2022 and say which one in real figures is more expensive?