Population of Taylor County is 21000
The population declines by 10% every year
Since it declines by 10% everywhere i.e the declination is at a constant percentage, the population left after every year in % will be

Let n represent the number of years,
To find the population left, the formula is

For two years, i.e n = 2
The population left in 2 yearswill be

Hence, the population left in 2 years is 17010