The population of a town was 25,000 in the 2000 census and 30,000 in the 2010 census. By what percent did the population increase?

This means that the population increased a 20% between the year 2000 and the year 2010.

Step-by-step explanation:

In this case, we have that 25,000 is the 100%.

Now we want to know which percentage represents 30,000

Let's suppose that the percentage is X.

Then we can have a system of equations:

30,000 = X

25,000 = 100%

To find the value of X, we can take the quotient of these two equations:

30,000/25,000 = X/100%

(30,00/25,000)*100% = X = 120%

Then in the 2000 we had a 100%, and in the 2010 there was a 120%.

The difference is:

120% - 100% = 20%

This means that the population increased a 20% between the year 2000 and the year 2010.