Final answer:
To determine the maximum number of guppies for an aquarium, divide the aquarium's volume by the volume required per guppy (5 liters). Without knowing the total volume of the aquarium, an exact number cannot be provided.
Step-by-step explanation:
If one guppy requires 5 liters of water to live happily, and the aquarium can hold a total volume of water, we can calculate the maximum number of guppies by dividing the aquarium's volume by the volume required per guppy. The volume of water required for one guppy is given as 5 liters. To find out the maximum number of guppies that should be kept in an aquarium, we need to know the total volume of the aquarium. Since this specific information is not provided in the question, we cannot provide an exact number. Normally, you would divide the total volume of the aquarium (in liters) by 5 to obtain the maximum number of guppies that can live happily in that aquarium. The answer choices provided (a) 10, (b) 15, (c) 5, or (d) 20 seem to be for a theoretical scenario where the total volume of the aquarium is not stated.