If a 4 digit no.is randomly chosen,then what is the probability(approximately) that it is a perfect square?
a)0.0060 b)0.0600 c)0.0070 d)0.0076

• Total no. of 4-digit no's are 10000-1000 = 9000
  Perfect square 4-digit no. starts from 1024 which is the square of 32 nd ends in 9801 which is the square of 99...
  So No. of 4-digit numbers which are perfect squares are 99-31 = 68
  Prob. ll be = 68/9000 = 0.00755 = 0.0076
  
  Ans : (d) 0.0076
• 9 years agoHelpfull: Yes(66) No(0)
• There are 99 no below 9999 which are perfect squares but upto 31^2 it is a 3 digit no. So there are (99-31)=68 no. from 32 to 99 which are perfect squares and of 4 digit no in total of (1000-9999)=9000 nos. So Prob = 68/9000=0.00755
• 9 years agoHelpfull: Yes(3) No(0)
• Absolutely right boyz and gals! This tym problem solving section's question pattern changed arrangement questionhad been removed
• 9 years agoHelpfull: Yes(1) No(0)
• there are total 68 number which are perfect square below 10000
  total four digit number=9000
  p=68/9000=0.0076
  so ans is d
  
• 9 years agoHelpfull: Yes(1) No(0)
• according to problem
  4 digit numbers are 1000 to 9999
  so find how many numbers between them
  an = a+ (n-1)d
  an=9999, a =1000 , d=1 , n =?
  n= (9999-1000)/1+1(according to forumula )=9000 ( total 4 digit numbers)
  now finding the perfect square
  checking 32*32=1024 (smallest number) starting point
  33*33= 1089
  ....
  .......
  99*99=9801
  
  so total numbers between 32 to 99
  (an- a)/d +1
  (99-32)/1 +1=68
  so now probability 68/9000=0.00755555555555555555555555555556 so answer is d
• 7 years agoHelpfull: Yes(1) No(1)
• 2 was not in option
• 9 years agoHelpfull: Yes(0) No(0)
• perfect square=(prime)^even...
  like according to question=37,41,43,53,59,61,67,71,73,79,83,89,91,93,97 total of 16
  and the required probability is 16/9000=.001777
• 8 years agoHelpfull: Yes(0) No(0)