A millionaire bought a job lot of hats 1/4 of which were brown. The millionaire sold 2/3 of the hats including 4/5 of the brown hats. What fraction of the unsold hats were brown.  Choices:
A) 1 / 60  B) 1 / 15  C) 3 / 20  D) 3 / 5  E) 3 / 4

Rationale: if initially he had x hats . x / 4 were brown . sold x * 2 / 3 hats . left with x / 3 hats . sold ( x / 4 ) * ( ( 4 / 5 ) = x / 5 brown hats and left with x / 4 - x / 5 = x / 20 brown hats . fraction of brown hats in total remaining hats = ( x / 20 ) / ( x / 3 ) = 3 / 20 hats answer : c
Answer: C