Campus Publishing prints textbooks written by faculty and distribute around the world. The Business English book is particularly popular and has annual sales of 100,000 copies per year. Printing each copy of the book costs $60. The author is encouraged to come up with revisions (i.e., new editions) to cater to consumer needs. Each revision will require $250,000 for a new typeset of the book. After a new edition is released, its sales value is discounted at a rate of $2 every 3 months. How frequently should new editions be published?