a prob about coins
alright this peoblem might sound familiar... but somebody please post the solution asap
the q is
there are 12 coins... all are samilar but one..
one has a mass defect ie could be more or less
you have a weighing balance( for convienence take any balance... phy ... tarazu... electronic etc etc)
and got only 3 weighings to find that defective coin....
anybody who comes with the soln please post it.... and if only in certain ciricumstances( like assuming the weight of the coins).. then do mention it
happy solving
the q is
there are 12 coins... all are samilar but one..
one has a mass defect ie could be more or less
you have a weighing balance( for convienence take any balance... phy ... tarazu... electronic etc etc)
and got only 3 weighings to find that defective coin....
anybody who comes with the soln please post it.... and if only in certain ciricumstances( like assuming the weight of the coins).. then do mention it
happy solving
posted by Abhishek Jain at 6:34 PM
11 Comments:
The solution is:-
This solution will require a beam balance.
Divide the 12 balls into groups of 4. We will have 3 groups with us. Choose any two groups and put them on either side of the balance. If we have chosen a group which contains the odd ball then the balance will lower to its side and we have the group which contains the odd coin. If otherwise the balance remains in equilibrium then the group that we haven’t chosen is the one with the odd coin.
Now we are left with four coins and we have only used one weighing.
Again divide the four coins into groups of two and weigh. By applying the same concept as in the first case we will get two coins one of which is the odd one. Mind it that I still have one more weighing to go and have two coins left.
Now if anyone still wants me to write the last step to get the odd coin then that person should please stop posting messages on this blog.
yeah the solution cant be this simple
okay i did not read the more or less carefully
wat u can do is that you can divide the 12 coins into three groups and c whch one has an unequal weight but then again the no of weighings issue comes into the scene...well...keep thinking ppl :)
isnt it taht coins sink in water buh suppose that coin dsnt sink...okay...or maybe u could each coin to a string and measure the distance b/w the ground and the coin the one which is diff mite be the diff coin...otherwise it seems impossible with the weighing option
abey, bhenchod, put the coins in your gand, whichever coin smells more of your gand that's the defective coin. :-)
woah...woah....applause man!!
but then wat is the solution?????
i dont noe....abhishek (jain) learnt those 2 words that day 'gand and bhanchodh' and he spells it as bhenchodh so maybe thats him.
now we do noe that anonymous can be restricted....btw huu is the admin???
oh me god!
a blog full of problems!
you people are really enthu-driven iit aspirants...
best of luck guys
Varenya and myself are the admins Dhruv and it was me who blocked anonymous comments.
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