Answer:
100%
Explanation:
The mark-up percentage is the amount by which the cost price of a product is increased to arrive at the selling price. To calculate the mark-up percentage, you can use the formula:
Mark-up percentage = (selling price - cost price) / cost price x 100
In this case:
Cost price = $450
Selling price = $900
Mark-up percentage = ($900 - $450) / $450 x 100 = 100%
So the specialty shop has a mark-up of 100% on each painting.
It means that the shop is charging twice as much as the price they procured the paintings.