shortcut trick for profit and loss

just keep the formula in your mind before solving profit and loss question.. Like

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 sold, is called its selling prices, abbreviated as S.P.
Profit/gain = SP – CP
Profit % = Profit/(C P)×100
S P = (100+gain % )/100  ×C P
C P = 100/(100+gain %)×S P
Loss: 
If the overall Cost Price exceeds the selling price of the buyer then he is said to have incurredloss.
Loss = C P – S P
Loss % = LOSS/(C P)×100
S P = (100-loss %)/100×C P
C P = 100/(100-loss %)×S P