Final answer:
Without additional data about the total population of Springfield or the average number of households owning a swimming pool, it is not possible to accurately estimate the number of people with swimming pools from the provided choices. The piece of information given indicates an estimated population size of 400 individuals, but this option is not among the multiple-choice answers provided.
Step-by-step explanation:
To estimate the number of people in Springfield with swimming pools, we would need additional information that is not provided in the question such as the total population of Springfield, the average household size, and the percentage of households that typically have a swimming pool.
However, using the given pieces of information, we can analyze the provided options. The last piece of information suggests that the estimated population size is 400 individuals. If this refers to the number of individuals who have a swimming pool, then the correct answer would be that 400 people might be expected to have a swimming pool, which is not listed in the given choices (a), (b), (c), or (d). Hence, we lack the necessary data to choose from the options provided.
It's also important to note that part of the question references other unrelated calculations, such as the time it takes to fill a swimming pool using a garden hose or a river. These are distractors and are not relevant to estimating the number of people with swimming pools.