At Joel’s bookstore, the current inventory is 30% historical fiction. Of the historical fiction books, 40% are new releases, while 50% of the other books are new releases. What fraction of all new releases are the historical fiction new releases? Choose the correct choice from the following answers:  A) 4 / 25  B) 12 / 47  C) 2 / 5  D) 8 / 15  E) 2 / 3

Rationale: let there be 100 books in all historic fiction books = 30 % of total = 30 other books = 70 new historic fiction = 40 % of 30 = 12 other new books = 50 % of 70 = 35 total new books = 35 + 12 = 47 fraction = 12 / 47 ans : b
Answer: B