Chapter B.1, Problem 24E

To determine

the percentage rate of decrease in price from 2009 to 2013.

Answer to Problem 24E

The percentage increase in price from the year 2009 to 2013 is $54.16\%$ .

Explanation of Solution

Given information:

The given line graph of the average price of gasoline is

  

Formula used:

Formula of percentage decrease:

  $\%increase=\frac{finalvalue-initialvalue}{initialvalue}\times 100$

Note the average price of gasoline in the year 2012 and 2016 from the above graph.

  $2009=\$2.40/\text{gallon}$

  $2012=\$3.70/\text{gallon}$

Calculate the percentage increase using the formula:

  $\%increase=\frac{finalvalue-initialvalue}{initialvalue}\times 100$

Substitute $\$2.40/\text{gallon}$ for initial value and $\$3.70/\text{gallon}$ for final value in the above expression.

  $\begin{array}{c}\%decrease=\frac{3.70-2.40}{2.40}\times 100\\ =54.16\%\end{array}$

Hence, the percentage decrease in price from the year 2009 to 2012 is $54.16\%$ .