720 GAZELLE FLIP
There was a window cleaner who was cleaning a window on the 25th floor of a skyscraper. He suddenly slips and falls. He has no safety equipment and nothing to soften his fall, but he is not hurt at all. How is this possible?
At a fast food outlet, you order chicken wings in boxes of 6, 9 and 20. Then, what is largest number of wings that is not possible to get if you purchase some combination of boxes?