find the probability of x^2-1 divisible by 72 condition is x>=10.
options:
a) Never
b) 1/6
c) 1/5
d) 1/9

• As per your explanation this also will be considered in your event 53*53=2809-1=2808/72=39 and we never know how many possible factor of 72 we will be, hence 1/5 is not correct.
• 10 years agoHelpfull: Yes(1) No(0)
• first number is 17
  2nd number is 17+2=19
  3rd number is 19+34=53
  4th number is 53+2=55
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  its in series of 34 and 2, so 1/5 is not correct, what will be probability?
• 10 years agoHelpfull: Yes(1) No(0)
• 1/5 is the answer
  coz 17^2-1 and 19^2-1 is divisible by 72
  so 2/10==1/5
• 10 years agoHelpfull: Yes(0) No(1)
• question is incomplete. it was given in the paper that x is divisible by 72
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• please mention the upper bound value plzz. orelse the ans is never
• 10 years agoHelpfull: Yes(0) No(0)