Question: James has an old printer that crumples every seventh page and blurs the ink on every third page. If he prints 42 pages, how many are neither crumpled or blurred? Think carefully first, then make a decision:
First find the total number of pages that are crumpled: 42 pages / 7 = 6 pages. Then find the total number of pages that are blurred: 42 pages / 3 = 14 pages. Then find the number of pages that are both blurred and crumpled by finding how many numbers are less or equal to 42 and divisible by both 3 and 7: there are two, 21 and 42. Then subtract the number of crumpled and blurred pages from the total number of pages, and add the number of pages that were double - counted because they were both blurred and crumpled: 42 pages - 6 pages - 14 pages + 2 pages = 24 pages. So the answer is 24.