The U and inverted U symbols, ∪ and ∩, are mathematical symbols used to denote union or intersection, respectively. For example, when a rational algebraic equation is graphed, there may be some points where the equation is undefined. Visually, we see it as breaks or discontinuities. We use the ∪ symbol to express union. For example, {-∞,2)∪(4,+∞). That means that the graph passes at all x values except x=3.
The ∩ symbol is used for intersection of two lines, for instance. When equation A and equation B are graphed, they can intersect at points (x,y). It is therefore expressed as: A∩B = (x,y).
The ratio of red marbles to blue marbles is 3:2, so for every two blue marbles there are three red marbles. This means that there are three red marbles for every four marbles in the bag. Therefore, if there are five marbles in the bag, there must be three red marbles and two blue marbles.
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