Question

The 2010 census reported about 308.7 million people in the U.S. The 2000 census reported a population of about 281.4 million. By about what percent did the population change?

Answer 1

well, in 2000 it was 281.4

in 2010 it went up to 308.7

308.7 - 281.4 = 27.3

so, if we take 281.4 to be the 100%, how much is 27.3 off of it in percentage then?


`\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 281.4&100\\ 27.3&p \end{array}\implies \cfrac{281.4}{27.3}=\cfrac{100}{p}\implies p=\cfrac{27.3\cdot 100}{281.4}`