Question

Ten percent of the class period was spent taking roll and making announcements. If there were 45 minutes that remained, how long is the class period?

Answer 1

Let the class period be x

10% of x is

`=(10)/(100)* x=0.1x`

If the remaining time is 45 minutes, i.e

`x-0.x=45`

Solve for x to find the class period

`\begin{gathered} x-0.x=45 \\ 0.9x=45 \\ \text{Divide both sides by 0.9} \\ (0.9x)/(0.9)=(45)/(0.9) \\ x=50\min \end{gathered}`

Hence, the class period, x, is 50 minutes