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William is taking the 25-question, multiple choice American Mathematics Competition. Each question has five answer choices. William guesses random answers for the last four questions. What is the probability that he will get at least one of these final four questions right?

 

Thank you!

 Mar 25, 2021
 #1
avatar+121004 
+2

(Binomial) Probability  =   1  -  probability  that  he gets none correct  =

 

1 -  (4/5)^4   =

 

369/ 625  ≈ 

 

59%

 

CORRECTED.....

 

 

cool cool cool

 Mar 25, 2021
edited by CPhill  Mar 25, 2021
edited by CPhill  Mar 25, 2021
 #2
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+1

Sadly this is incorrect. Thank you for trying though!

the correct answer is 369/625

Guest Mar 25, 2021
 #3
avatar+121004 
+1

Sorry...slight error...I  figured  for 5 questions instead of 4....see my corrected answer

 

 

cool cool cool

CPhill  Mar 25, 2021

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