arunachalamit

 Profile Answers by arunachalamit 

• Sep 21st, 2008

 

split the coin into 26 26 26......
take any 2 26 coins.....
if it is = the odd coin isin remaining 26,
if any one has less or more wt, go for nxt and find it..
so it takes 2 trials.....
9,9,9
3,3,3
1,1,1.....

5 trials or 6 trials

avin2v2

 Profile Answers by avin2v2 

• Oct 5th, 2008

 

consider 2 coins no of ways 2 find the counterfeit coin is 1
consider 3 coins no of ways 2 find the counterfeit coin is also 1
  since for testin u ll tak 2 coins in tat if none is counterfeit then the 3rd coin not taken for testin is counterfeit coin or in other case if a counterfeit coin is present in 2 coins tat u hav taken for testin u cud directly find out
so 1test is enough for 3coins
so split 80coins in terms of 3
(27,27,26) to find the counterfeit ( set) we require 1 test
 among de set 27 or 26 split as
 (9,9,9) or (9,9,8) which requires 1 test to find counterfeit ( set)
 among de set 9 or 8 split as
 (3,3,3) or(3,3,2) which requires 1 test to find counterfeit ( set)
among de set 3 or 2 split as
 (1,1,1) or (1,1,0) which requires 1 test to find counterfeit coinnnnnnn
so exactly 4 tests are required

mus.shah

 Profile Answers by mus.shah 

• Nov 2nd, 2009

 

40 40
20 20
10 10
5    5
2     2
1      1

so total no of weighings are 6 .

aniket.par

 Profile Answers by aniket.par 

• Dec 20th, 2009

 

80 coins divided as 27,27 and 26 coins..

then 27 is divided as 9,9,9 or 26 is divided as 9,9,8

then 9 is divided as 3,3,3 or 8 as 3,3,2

and finally 3 as 1,1,1 or 2 as 1,1

so finally minimum number of weighing required= 4 

santhakumar.mit

 Profile Answers by santhakumar.mit 

• Aug 27th, 2010

 

80 coins divided as 27 27 and 26 coins..
then 27 is divided as 9 9 9 or 26 is divided as 9 9 8
then 9 is divided as 3 3 3 or 8 as 3 3 2 and
finally 3 as 1 1 1 or 2 as 1 1
so finally minimum number of weighing required 4
This one is correct one