A ready solution to the problem. The sorcerer of Arutyunov. Task number 528.

521-530. Solve the problem in probability theory

528. The probability of occurrence of an event in each of the identical and independent trials is 0.8. Find the probability that in 125 trials the event will come at least 75 and not more than 90 times.

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Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)