Find the probability that a year chosen at random has 53 Mondays.
1) 5/28
2) 3/28
3) 1/28
4) 2/28

• There are 2 kinds of year
  
  Leap year - probability =1/4(ie out of 4 years one is a leap year)
  Non leap year - probability =3/4
  
  So it's either this OR that
  
  Now in non leap year, there are 365 days meaning 52 Weeks with one day extra
  That one day can be Monday out of 7 possible days.Hence the probability =1/7
  
  Similarly in leap year, there are 366 days and so 366/7= 52 Weeks with 2 days Extra
  Now probability of occurrence of Monday out of possible 7 days =2/7
  
  So what we essentially want is
  (A non leap year AND Monday) OR ( A leap year AND Monday)
  
  So it'll be [3/4*1/7] + [1/4*2/7]=0.178
• 8 years agoHelpfull: Yes(3) No(0)