Assume There Are Two Goods in an Economy: Bread and Bottled

Essay

Assume there are two goods in an economy: bread and bottled water. Assume bread sells for $2 per loaf and water sells for $1 per gallon the first year and in the second year the price of a loaf rises to $2.50 and bottled water rises to $1.25. Why is averaging these two prices meaningless in terms of trying to figure out whether or not there is inflation in the economy?