A dishonest grocer professes to sell pure butter at cost price, but he mixes it with adulterated fat and thereby gains 25%. Find the percentage of adulterated fat in the mixture assuming that adulterated fat is freely available.
20%
30%
33.33%
40%
25%
Let the adulterated fat = 0 Rs.
Butter = Rs 1
C.P of mixture = 1x 100 /125 = 4/5 Rs
=1:4 of adulterated fat = 1/5x 100 = 20%