When both printers N and P are used, a collection of books can be printed in 4 hours. While printing, Printer N broke down. As a result, it took 3 hours to complete printing. If it would take Printer P 12 hours to print the collection alone,
- How long would it take to print the collection of books using only Printer N? Express your answer in hours.
- How long was Printer N used before it broke down? Express your answer in hours.