Present population of town = 22000
Rate of increase in population annually = 10%
Let the population 1 year ago be x .
Now,
(x + 10% of x) = 22000
(x + x/10) = 22000
11x/10 = 22000
x = 22000 x 10/11
x = 20000
So,
The population 1 year ago will be 20000.