There are 4 red, 3 blue, 3 yellow and 1 white marbles in Julie's Pocket. Without looking at the marbles, Julie draw 4 marbles from her pocket at once. How many marbles must Julie draw at most before she get 3 marbles of the same colour?

She will have to take out a number equal to the sum of all the marbles less the number of marbles in the smallest group of colored marbles plus one marble. Therefore, the number of marbles to be removed to ensure success would be = 11 - 3 + 1 = 9. Had all colored groups of marbles been identical in number, say 4, the number needed to be withdrawn to ensure success would be = 12 - 4 + 1= 9.