Question 1166792
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This problem came to the forum couple of days ago,


and I reacted, giving the full instructions on its solution.



https://www.algebra.com/algebra/homework/Probability-and-statistics/Probability-and-statistics.faq.question.1148030.html



Now it came again, and it makes me very sad,


because I see that the visitor even did not try to do elementary calculations on his (or her) own.