Answer
At the beginning of the 3 year period, the population was 589,125 people.
Work Step by Step
581,600+7525
The number you start with is 581,600. You need to add 7,525 to the population number since it says that the population decreased by 7,525 in 3 years. So, to get your answer, you add 7,525 to 581,600 in order to find the population before the decrease in population.