3)Of sub-clusters of positive integers {1,2,3}, {3,4,5,6}, {6,7,8,9,10}, {10,11,12,13,14,15} .. . {36, 37.38, ... 55} are clusters. This sets a 3-element subsets of the card is written and thrown into the bag. 3 cards are drawn at random bag. What is the sum of the numbers likely to be smaller than 100 by the cards?

4)Coordinate of a point over the rational number is actually the number likely to be selected at random what is the value?