Question

You have a rack that can hold $30$ CDs.

You can fit $7$ more CDs on the rack before the rack is full.

How many CDs are in the rack?

Answer 1

To find the number of CDs in the rack:

Let $x$ be the number of CDs on the rack.
The total number of CDs that can be held in the rack is $30$ CDs.

Since $7$ more CDs can be fit on the rack before the rack is full,

So, the total number of CDs in the rack before it gets full is below :
$\begin{array}{rcl}x+7& =& 30\\ & \Rightarrow & x+7-7=30-7\\ \therefore x& =& 23\end{array}$
Hence, $\mathbf{23}$ CDs are in the rack.