The CPI takes a constant basket of goods and sees how the price changes from year to year. If the price of the basket of goods increases, then there is price inflation. If the price of the basket of goods decreases, then there is deflation.
Copper and tin mainly make up bronze but other elements include phosphorus, manganese, silicon and aluminium.
Any alloy, or mixture, of copper and zinc is called brass. Sometimes small amounts of other metals are also included. In ancient times, metalworkers did not know the difference between zinc and tin, which when alloyed with copper makes bronze. As a result, both brass and bronze were for a time believed to be bronze.