Quantity of water Alberto had initially = 15 gallons.
Fraction of water that evaporated = 3/40
Now we have to find how much water is left.
Quantity of water left = Quantity of water Alberto had initially - Quantity of water evaporated.
Now let us find Quantity of water that was evaporated.
Quantity of water evaporated = 3/40 of 15 = 1.125 gallons
Quantity of water left = Quantity of water Alberto had initially - Quantity of water evaporated.
Quantity of water left = 15- 1.125 = 13.875 gallons
Answer: Quantity of water left is 13.875 gallons.
