A dishonest grocer professes to sell pure butter at cost price, but he mixes it with adulterated fat and thereby gains 35%. Find the percentage of adulterated fat in the mixture assuming that adulterated fat is freely available?
Options
A) 20%  B) 25%  C) 33.33%  D) 40%  E) 30%
Say 100g pure butter costs $100   But; $100 is his 35% profit because he just used 80gram pure butter.   80g would have costed him $80 and he sold it for $100 by adding 20g of freely available fat. $100 is 1.35(70)   so;   total weight=100g   fat=30g   30%   30%
<result>E</result>
A dishonest grocer professes to sell pure butter at cost price, but he mixes it with adulterated fat and thereby gains 35%. Find the percentage of adulterated fat in the mixture assuming that adulterated fat is freely available?