As the buyer at OhaganBooks.com you are planning to increase stocks of books about music, and have been monitoring worldwide sales.

As the buyer at OhaganBooks.com you are planning to increase stocks of books about music, and have been monitoring worldwide sales. Last year, worldwide sales of books about rock, rap, and classical music amounted to 5.8 billion. Books on rock music brought in twice as much revenue as books on rap music and they brought 900% the revenue of books on classical music. How much revenue was earned in each of the three categories of books?