Final answer:
The fish tank holds 36/5 gallons of water.
Step-by-step explanation:
To find the number of gallons of water the fish tank holds, we can use the information provided. Isabella fills her fish tank using a water jug that holds 4/5 of a gallon of water. She uses 9 full jugs to fill the tank.
Multiply the capacity of the jug by the number of jugs used:
4/5 * 9 = 4/5 * 9/1 = 36/5
So, the fish tank holds 36/5 gallons of water.