Question

Last week, you finished level $2$ of a video game in $32$ minutes. Today, you finished level $2$ in $28$ minutes. What is your percent of change?

Answer 1

Find the percent of change:

It is given that, the time taken to finish level $1$ is $32$ minutes. Then,

$T_1=32\min$

And the time taken to finish level $2$ is $28$ minutes. Then,

$T_2=28$

So, the percentage change can be calculated as:

$\begin{array}{rcl}P& =& \left(\frac{T_2-T_1}{T_1}\right)\times 100\\ & \Rightarrow & P=\left(\frac{28-32}{32}\right)\times 100\\ & \Rightarrow & P=\frac{-4\times 100}{32}\\ & \Rightarrow & P=-12.5\end{array}$

Therefore, the percent of change is $\mathbf{12}\mathbf{.}\mathbf{5}\mathbf{\%}$ and it is decreasing.