Final answer:
To find out how much water Jessica's family used this month, we can start by finding the 30% increase in water usage compared to last month's 12000 gallons.
Step-by-step explanation:
To find out how much water Jessica's family used this month, we can start by finding the 30% increase in water usage compared to last month's 12000 gallons.
To do this, we can multiply 12000 by 0.30 to find the amount of increase, which is 3600 gallons.
Finally, we add this increase to last month's usage: 12000 + 3600 = 15600 gallons.