To find the selling price of the office chair after marking it up by 28%, we can use the following equation:
\[ \text{Selling Price} = \text{Cost Price} + (\text{Markup Percentage} \times \text{Cost Price}) \]
In this case, the cost price (CP) is $63, and the markup percentage is 28%, which can be expressed as a decimal (0.28). Therefore, the equation becomes:
\[ \text{Selling Price} = 63 + (0.28 \times 63) \]
Alternatively, you can express this in a single equation as follows:
\[ \text{Selling Price} = 63 \times (1 + 0.28) \]
So the final equation for the selling price would be:
\[ \text{Selling Price} = 63 \times 1.28 \]
This equation can be used to calculate the selling price of the office chair.