For questions 3‒4, let X = {x | x is a whole number less than 15}, Y = { x | x is a multiple of 3 less than 15 }, Z = {x | x is a real number greater than or equal to 5.5}.
What is XUY?
XUY is the union of the sets X and Y.
The set X consists of whole numbers less than 15, so X = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}.
The set Y consists of multiples of 3 less than 15, so Y = {0, 3, 6, 9, 12}.
The union of sets X and Y, XUY, will contain all the elements that are in X or Y or both. So, XUY = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}.