Answer: 9384
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In the year 2010, the population is P = 22000 which is the starting population. The rate is r = -0.028 indicating a decrease of 2.8% annually
A = P*(1+r)^t
A = 22000*(1+(-0.028))^t
A = 22000*(1-0.028)^t
A = 22000*(0.972)^t
Now plug in t = 30 to compute the population in the year 2040 (which is 30 years after 2010)
A = 22000*(0.972)^30
A = 22000*0.42656768
A = 9384.48896
A = 9384 .... rounding to the nearest whole number