One must remember that there are two common ways to do "Markup"
1) We have demonstrated above: Markup as a percentage of the Cost. There is ni upper bound to this type of markup.
(Cost + 0.40*Cost) = 1.40*Cost = Price = $63.00
Cost = $45.00
$63.00 - $45.00 = $18.00 = Markup of the first kind.
2) Not demonstrated is: Markup as a percentage for the selling price. Some like this better, as it has an upper bound.
$63.00 * 0.40 = $25.20 = Markup of the second kind.
$63.00 - $25.20 = $37.80 = Original Cost
If you are consulting with any business, you must make sure you know which one they like. Maybe both.