There are 6561 balls out of them 1 is heavy.Find the min. no. of times the balls have to be
weighed for finding out the haevy ball.

• 1)6561/3=2187->2187,2187,2187
  2)2187/3=729->729,729,729
  3)729/3=243->243,243,243
  4)243/3=81->81,81,81
  5)81/3=27->27,27,27
  6)27/3=9->9,9,9
  7)9/3=3->3,3,3
  8)3/3=1->1,1,1
  8 times required
• 11 years agoHelpfull: Yes(47) No(4)
• 3^n = N
  3^8 = 6561
  so ans = 8
• 14 years agoHelpfull: Yes(28) No(17)
• consider 3 balls, u can find the heavier by just weighing 2 balls,now minimum will be 1.Next consider 9 balls, divide them into 3 equal groups, now u can weigh 2 groups to find the group in which the heavier ball lies, and u ll be left with 3 and u know how to find out of 3. so its 3 pow 2 = 9, then 3 pow 3 = 27...... 3 pow 8 = 6561. So the ans is 8.
• 11 years agoHelpfull: Yes(25) No(1)
• Weigh 1/3 of the number of balls against another 1/3.
  If they are equal, the heavy ball is in the 1/3 that you didn't weigh.
  
  Each weighing eliminates 2/3 of the number of balls.
  6561 = 3*8 so you need 8 weighings.
• 12 years agoHelpfull: Yes(12) No(6)
• guys why we r dividing it from 3 , can we devide it 9.
• 10 years agoHelpfull: Yes(11) No(6)
• why u are taking 3 for power or dividing ?
• 10 years agoHelpfull: Yes(7) No(2)
• 6561/81=81 times
  
  81/9=9 times
  
  9/9=1 times
  
  so minimum no of times is 3..
• 10 years agoHelpfull: Yes(7) No(8)
• why three (3) means
  let consider the balls divided into a,b,c groups , we know that only one ball is heavier i.e,.. that may be present in a or b or c.
  suppose if we measure(compare) a and b groups
  if a>b then we know that definately heavy ball is in "a "group
  if a
• 7 years agoHelpfull: Yes(2) No(0)
• do{ Keep on dividing all balls in 3 groups
  Now weigh any two groups
  if they are equal
  the third group contains the heavy ball
  else
  the heavier one contains the heavy ball
  end
  }whlie(we get the only heavy ball)
  
  
  So number of times we weigh will be log3(6561)=8
• 9 years agoHelpfull: Yes(1) No(1)