probability that the 13th day of a randomly choosen month is a friday

• pr0bability of choosing any month out of 12 months = 1/12
  
  the month can start with any of the seven days, but 13th day of a month is friday
  iff first day of month is sunday , its probability = 1/7
  
  reqd probability = 1/12 * 1/7 = 1/84
• 10 years agoHelpfull: Yes(39) No(3)
• please give another solution and solution should be clear
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• please submitt correct solutions not ur own soltns
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• prob of choosing any month out of 12 months = 1/12
  
  if 13%7====6
  
  soo if 8th of month is
  
  ************** 8 9 10 11 12 13
  
  If SUN then... S M T W T F
  If MON then... M T W T F S
  If TUE then... T W T F S S
  If WED then... W T F S S M
  If THU then... T F S S M T
  If FRI then... F S S M T W
  If SAT then... S S M T W T
  
  in first case only(If 8 th of month is SUN) 13 of month is Friday... out of cases---->>>> 1/7
  
  ans is...(1/12)*(1/7)
• 9 years agoHelpfull: Yes(1) No(0)
• It says any month , so you can choose any month from 12 months in a single way only I guess, and the 13th day to be Friday the first day has to be Saturday which is possible in 1/7 way
  So ans would be 1/7
• 9 years agoHelpfull: Yes(1) No(0)
• 1/3
  bcoz 13%7=6 so in these 6 days probability of choosin friday is 2 frm mon to sat nd sun to fri so
  1/6+1/6=1/3
• 10 years agoHelpfull: Yes(0) No(3)
• question invalid(if 13th day is to be friday,then 1st should be on monday)
  Reason:In 2013 '2 Months' Have 13th day friday
  2012 '3 months'
  2011 '1 month'...so on randomly.So question needs to be modified
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• The 13th day of a month can be any day from a week of 7 days.
  so,required probability is 1/7
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• choosing month prob=1/12
  13th day friday prob=1/7
  prob=1/12*1/7
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• plz sbmt crct sltn
  
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• can anybody xpln it clearly
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• plz submit crrct solution
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