Population of town was 21000 in 1980 and it was 20000 in 1990. Assuming the population is decreasing continuously at a rate proportion to the existing population, estimate the population in 2010.

19,000

Step-by-step explanation:

Here, we are to estimate the population in the year 2010

From the question, we can see that within a period of a decade which is 10 years, 1000 was lost

So within the period of another decade, it is possible that another 1000 be lost

The estimated population in the year 2010 is thus 20,000 - 1,000 =

19,000