Give the step-by-step reasoning process and then the final answer. Cameron is printing her thesis in the school library and has 400 A4 pieces of paper. If 40% of the papers did not print out up to her desired quality and she separated them as invalid, calculate the total number of valid documents.
If she had 400 papers, the total number of documents she separated as invalid is 40 / 100 * 400 pages = 160 pages. The number of valid documents is 400 pages - 160 pages = 240 pages.
The final answer: 240.