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MATH / 5 white balls and k black balls are placed into a bin. Two of the balls are drawn at random. The probability that one of the drawn balls is white and the other is black is …

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problem

5 white balls and kk black balls are placed into a bin. Two of the balls are drawn at random. The probability that one of the drawn balls is white and the other is black is 1021\frac{10}{21}. Find the smallest possible value of kk.
Plain-text mathematical notation (without MathML)
5 white balls and k black balls are placed into a bin.  Two of the balls are drawn at random.  The probability that one of the drawn balls is white and the other is black is (10)/(21).  Find the smallest possible value of k.
Original LaTeX notation
5 white balls and $k$ black balls are placed into a bin.  Two of the balls are drawn at random.  The probability that one of the drawn balls is white and the other is black is $\frac{10}{21}$.  Find the smallest possible value of $k$.

level

Level 4

type

Counting & Probability

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