where is the population after time , is the initial population, is the rate of growth, and is time
since it grows from 81,500 to 103,200 over a 7 year period, we have:
solve that for , that will give you the rate of growth.
then use it to find what they asked you for, which would be to solve:
for (you will know the value of at this point, the value of is immaterial)