Question

Which equation shows when the average cost per month (m)of joining the swimming club would be $30?

Answer 1

`\begin{gathered} 30=(20m+40)/(m) \\ 4\text{ months} \end{gathered}`

Step-by-step explanation

It costs $40 upfront to join the club and $20 per month.

Let the number of months be m.

This means that the equation that represents the equation that represents the total cost is:

`C=20m+40`

The average cost of joining the club is the total cost divided by the number of months.

That is the average cost will be $30 when:

`30=(20m+40)/(m)`

To find the number of months it will take for the average cost per month of joining the swimming club to be $30, we have to solve for m:

`\begin{gathered} 30=(20m+40)/(m) \\ 30m=20m+40\text{ (multiply both sides by m)} \\ \Rightarrow30m-20m=40 \\ 10m=40 \\ m=(40)/(10)\text{ (divide both sides by 10)} \\ m=4 \end{gathered}`

It will take 4 months.