# Question #dba1a

##### 1 Answer

Feb 21, 2017

#### Answer:

The population 2 years hence was 2000 people.

#### Explanation:

For each year, the end population is 90% of the starting population (100%). That means that:

and

So, to know the population from a year ago, we have to set up the following equality:

Now, with a little algebra we do the following steps to single out

1) multiply each side by

2) multiply each side by 100

3) multiply each side by

Leaving us with:

Now if we do the same process with 1800 to start with, we get the final equation: