Q. There are 27 pearls in a bag. One among them is less in weight. You have been given 2 pan weight machine. In how many trials, you will be able to find the defected one?

Option
a) 4
b) 3
c) 11
d) 13

• First we would take 13 perls in each pan and if we found that both are equal then the remaining perl(which has not taken for weighing) is having less weight or if there is an imbalance in either side of the pan we would consider those perls to find out the less weight perl. In this way there would be 4 stages at max to find out the less weighing perl by repaeting the same process as 1st. so answer is 4
• 11 years agoHelpfull: Yes(12) No(1)
• answer is 4
  
  27 = 13 13 1
  compare 13 13
  if equal 1 is the lowest weight if not divide 13 into 6 6 1
  compare 6 6
  if equal 1 is the lowest if not divide 6 into 3 3
  compare 3 3
  if not equal divide 3 into 1 1 1
  comapre 1 1
  if equal 1 is lowest weight
• 11 years agoHelpfull: Yes(12) No(1)
• its in 3 steps...
  9 9 9
  3 3 3
  1 1 1
  so in 3rd step we will be able to find out which one is lighter...
• 11 years agoHelpfull: Yes(8) No(7)
• DIVIDE THE 27 PEARLS INTO
  
  9 9 9 PEARLS
  
  AND WEIGH ANY ONE PAIR ----- 1
  
  THEN WE TAKE THE HEVIER 9 PERAL
  
  DEVIDE INTO 3 3 3
  AND WEIGH IT ----------2
  
  NOW WE GET 3 PEARLS IN WICH ONE IS HEAVIER THEN OTHER
  
  1 1 1
  
  WEIGH ANY TWO ------------3
  
  HENCE WE GET THE HEAWIER
  
  so total of 3 times.
• 10 years agoHelpfull: Yes(8) No(0)
• There is a pettern for these kind of questions.
  If the number of items are less than 3^n, we can find the different pearl in n times.
  As 27 is 3^3, we can find the required pearl in three times.
• 11 years agoHelpfull: Yes(3) No(10)
• 27
  trial 1. 13+13 on each weight machine if both is equal weight one which is not participated is less weight
  if one is less take 13 which is less one on the weight machine
  
  trial 2. 6+6 on each weight machine if both is equal weight one which is not participated is less weight
  if one is less take 6 which is less one on the weight machine
  
  trial 4. 1+1 on each weight machine if both is equal weight, one which is not participated is less weight
  if not you can see the weight machine to get less one
  
  so its max chance to get the less one is in 4 trails
• 7 years agoHelpfull: Yes(0) No(0)