5. given 8 different natural numbers, none greater than 15, show that at least 3 6. how many diagonals are there in a conver n-gon? for erample in a 4-gon 7. how many bit strings of length 8 contain two consecutive o's and two conseculive 8. how many strings of 3 letters (a, b, c) and length 6 contain one string aa or one pairs have the same positive difference. (quadrilateral) rthere are 2, in a 5-gon (pentagon) there are 5. 1's? string be?