Markdown

Mark down is decrease in the selling price. It is the difference in the old retail price and the new retail; that is ,
MD = OP - NP
Where MD = markdown
OP = old retail price
NP = new retail price

For example :

The markdown per cent on a TV set is 10%. If the new retail price is RM900, find the old retail proce.

Solution :
Let the old price be RM K.
From %MD = MD/OP X 100%, we get
10% = ( K- 900 ) / K
0.1K = K - 900
K - 0.1K = 900
K = RM 1000.