The balance of a trader weighs 20% less than it should. Still the trader marks up his goods to get an overall profit of 30%. What is the mark up on the cost price?
Choose the correct choice from the following answers
A) 4 % B) 8 % C) 25 % D) 16.66 % E) 9 %

Rationale: the most natural way to deal with ' weights ' questions is by assuming values . say the trader ' s balance shows 100 gms . it is actually 80 gms because it weighs 20 % less . say , the cost price is $ 80 ( $ 1 / gm ) . since he gets a profit of 30 % , the selling price must be 80 + ( 30 / 100 ) * 80 = $ 104 since the cost price is actually supposed to be $ 100 ( for 100 gms ) and the selling price is $ 104 , the mark up is simply 4 % . ans : a
Answer: A