Question

If Marvin’s music sold 18000 cds in 2000 and 21100 in 2005 what is the rate of change

Answer 1

`\bf \begin{array}{ccll} \stackrel{x}{year}&\stackrel{y}{CDs}\\ \cline{1-2} 2000&18000\\ 2005&21100 \end{array}~\hspace{10em} (\stackrel{x_1}{2000}~,~\stackrel{y_1}{18000})\qquad (\stackrel{x_2}{2005}~,~\stackrel{y_2}{21100}) \\\\\\ \stackrel{\textit{average rate of change}}{slope = m\implies} \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{21100-18000}{2005-2000}\implies \cfrac{3100}{5}\implies 620`

Answer 2

The rate of change is 620 cds because you would subtract the two and divide by the number of years (5) to get you answer.