Question

Population From 1990 to 2000, the population of Cresco, Iowa, increased by 236. The population in 2000 was 3905. Use an equation to find the population in 1990.

Short answer

Population in year $1990$ = $3669$.

Step-by-step solution

Step 1.  Calculating population in year 1990 

Let us assume that the population in year $1990$ is $x$.

From given information

Population of Cresco in year$2000$ $=3905$

It means

Population in year $1990$ $+$ Increase in population from year $1990$ to $2000$ $=3905$

Step 2.  Substituting given value

On substituting value, we get

$x+236=3905$

Step 3.  Solving for value of x

On subtracting $236$on both sides, we get

$\begin{array}{c}x+236-236=3905-236\\ x=3905-236\\ x=3669\end{array}$

$x=3669$

Therefore, the population of Cresco in year $1990$ $=x=3669$.