Q. From a bag containing 34 balls, one ball weighs 4 grams and all the other weigh 5 grams each. Using a simple balance where balls can be kept on either pan, what is the minimum weighs required to identify the defective ball?
Option
a) 4
b) 3
c) 7
d) 5

• 1. 17-17 >> select the lighter side,, now u have 17 samples remaining to test..
  2. 8-8 >> if both are balanced, this means that U R LUCKY and ball which u didnt put on balance, is the defected one.. ENDS only in 2 Steps.. Else go Step-3
  3. 4-4.
  4. 2-2.
  5. 1-1.
  So, 2&5 are the ans.
• 10 years agoHelpfull: Yes(24) No(4)
• its ans will be 4....
  17-17
  8-8..... 1 in hand,if 8 and 8 equal then 1 will be the ans otherwise
  3-3......2 in hand, if 3 and 3 equal then compare b/w remaining 2 otherwise
  1-1......1 in hand, if 1 and 1 equal then remaining 1 will be the ans.
• 10 years agoHelpfull: Yes(12) No(0)
• Ans b
  (10-10) - 14
  (5-5)
  (2-2-1)
  (1-1)
  
  ELSE
  14 7-7
  3-3-1
  1-1-1
  
  
• 10 years agoHelpfull: Yes(7) No(12)
• 5 bcz
  17-17
  8-8
  4-4
  2-2
  1-1
  
• 10 years agoHelpfull: Yes(6) No(1)
• 1.17-17=you will get one set in which heavy ball exist. similarly
  2.8-8-1=there will be change to get 1 ball as heavy if not than
  3.4-4
  4.2-2
  5.1-1
• 10 years agoHelpfull: Yes(3) No(13)
• Ans) d
  17-17
  8-8
  4-4
  2-2
  1-1
  
  
• 10 years agoHelpfull: Yes(2) No(2)
• step 1. 17-17=you will get one set in which heavy ball exist. similarly
  step 2. 8-8-1=there will be change to get 1 ball as heavy if not than
  step 3. 4-4
  step 4. 2-2
  step 5. 1-1
  so, the ans is (d)
• 10 years agoHelpfull: Yes(2) No(0)
• Ans:a
  (i.e)
  1)10-10
  2)5-5(thr may b chance a find a odd)
  else
  3)2-2
  4)1-1
  
  else
  1)take remaining 14 from (10-10-14)
  2)7-7
  3)3-3(thr may b chance to find odd)
  4)1-1
  
  Anyways the ans is 4
• 10 years agoHelpfull: Yes(1) No(1)
• there are 34 balls so apply log(34) to the base 2 and the answer will be 5.so option d
• 9 years agoHelpfull: Yes(1) No(0)
• 
  1. 2 comparison are required here bcoz if A,B is Balanced then Defective item will be in C,
  Group A: (7,7)
  Group B:(7,7)
  GroupC: (6)
  
  2. if Group A Or Group B is defective
  => (7,7) is defective
  
  Group D:(3,3)
  Group D:(1)
  
  now pic (3,3) , If unbalanced.............................................3rd comparison
  Group E:(1,1) is balanced then 3rd one is defective ............................................4th comparison
  otherwise item exist in (1,Defective)
  
  Answer. (a) i.e 4
• 8 years agoHelpfull: Yes(1) No(0)
• can someone explain the logic?
• 10 years agoHelpfull: Yes(0) No(0)
• b is the right answer.
  
• 10 years agoHelpfull: Yes(0) No(1)
• divide 34 into 2 i.e 17
  17 /2 i.e 8,5 so pan each 8 if one pan less then 8/2 4 again 4/2 =2
• 10 years agoHelpfull: Yes(0) No(0)