Let x = number of months.
Let y = total number of fish in pond.
6% of 3,000 = 180 fish
We can use an equation to help us with this problem.
y = 3,000 + 180x - 400x. Combine like terms.
y = 3,000 - 220x. Plug 9 in for x.
y = 3,000 - 220(9). Solve for y
y = 1,020.
There are 1,020 fish in the pond after 9 months.