Every year the typical family on Planet Econ consumes ten pizzas, seven pairs of jeans and 20 litres of milk.
In 2002 pizzas cost $10 each, jeans cost $40 per pair, and milk costs $3 per litre.
In 2003, the price of pizzas went down to $8 each, while the price of jeans and milk remained the same.
Between 2002 and 2003, a typical family's cost of living: Select one:
a. increased by 4.5%
b. decreased by 4.5%
c. increased by 20%
d. decreased by 20%