we know that
the Consumer Price Index
(CPI) is equals to
CPI=100*[cost of the pizza today/cost of the pizza in the base year]
[cost of the pizza in the base year]=100*[cost of the pizza today/CPI]
cost of the pizza today=$12
CPI=200
so
[cost of the pizza in the base year]=100*[12/200]-----> $6
the answer is
The cost of the pizza in the base year is $6
