Can someone help me with this? lolz

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Suppose i flip two identical coins. what is the probability that i get one head and one tail?

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

Which is the focus of a parabola with equation y2=4x