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 its cost price, abbreviated as C.P.

Profit or Gain : The price at which an article is purchased, is called its cost 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. = (100Loss%)/100 * C.P. 
8. 
C.P. = 100/(100+Gain%) * S.P. 
9. 
C.P. = 100/(100Loss%) * 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. 