Cost Price : The price at which an article is purchased, is called its cost price, abbreviated as C.P.
Selling Price : The price at which an article is purchased, is called itscost price, abbreviated as C.P.
Profit or Gain : The price at which an article is purchased, is called itscost price, abbreviated as C.P.
Loss : If S.Pis less than C.P., the seller is said to have incurred a loss.
1.	Gain = (S.P.) - (C.P.)
2.	Loss or gain is always reckoned on C.P.
3.	gain% = [Gain*100/C.P.]
4.	Loss = (C.P.) - (S.P.)
5.	Loss% = [Loss*100/C.P.]
6.	S.P. = (100+Gain%)/100 * C.P.
7.	S.P. = (100-Loss%)/100 * C.P.
8.	C.P. = 100/(100+Gain%) * S.P.
9.	C.P. = 100/(100-Loss%) * S.P.
10.	If an article is sold at a gain of say, 35%, then S.P. = 135% of C.P.
11.	If an article is sold at a loss of say, 35%, then S.P. = 65% of C.P.