Final answer:
The zookeeper can have a total of 6 swans in the rectangular habitat.
Step-by-step explanation:
To find out how many total swans the zookeeper can have in the habitat, we need to calculate the number of swans that can be accommodated with the given habitat area of 1000 square feet.
For the first 2 swans, the zookeeper needs to reserve 200 square feet for each, so a total of 200 x 2 = 400 square feet is reserved.
For each additional swan, 125 square feet is required. Let's assume the number of additional swans is 'x'.
So, the total area occupied by the additional swans is 125x.
Since the total habitat area is 1000 square feet, the equation becomes: 400 + 125x = 1000.
Solving this equation, we find x = 4.
Therefore, the zookeeper can have a total of 2 (first swans) + 4 (additional swans) = 6 swans in the habitat.