Answer:
decreased by 4.5%
Step-by-step explanation:
A family consumes: 10 pizzas, 7 pairs of jeans, and 20 gallons of milk.
In 2016, pizzas cost $10 each, jeans cost $40 per pair, and milk cost $3 per gallon.
The family's total cost of living in 2016 is:

In 2017, pizzas cost $8 each, jeans cost $40 per pair, and milk cost $3 per gallon.
The family's total cost of living in 2017 is:

The change, in percentage, of a typical family's cost of living is:

The cost of living decreased by 4.5%