Joe went to a store and spent 1/2 of his money on a book. He then spent 2/5 of his remaining money on a computer game. After that he spent 1/4 of his remaining money on a CD. Finally, he spent 1/6 of the reamining money on a candy bar. After buying the 4 items, he was left with $15. How much money did he have originally that is, before he purchased the book?