<human>:  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.
<bot>: How many pages did Cameron separate as invalid? ** If she had 400 papers, the total number of documents she separated as invalid is 40/100 * 400 pages = <<40/100*400=160>>160 pages.
How many pages are valid? ** The number of valid documents is 400 pages - 160 pages = <<400-160=240>>240 pages
#### 240