You have 6 coins of same type. One is fake and lighter than the rest.
How will you find the fake coin with only two weighings on the balance scale ?
Answers
Answer:
Not nearly as difficult as the the previous two problems of this type. Lets start as always by numbering them 1 to 9.
Put 1,2 & 3 on the left side and 4,5 & 6 on the right side. There are three possible outcomes:
scale tilts left - means the heavy coin is in group 1,2 & 3
scale tilts right - means the heavy coin is in group 4,5 & 6
scale balances - means the heavy coin is in group 7,8 & 9
Using one weighing we have successfully narrowed three groups down to one. If it's not completely clear how we can make the assumption that the bad coins is in group 7,8 & 9 when the scales balance, remember we know there is a bad coin, there has to be, we have eliminated the other two groups, it must be in the third.
We need to do the same again and we will arrive at the final coin. Lets label the three coins we have narrowed it down to as A, B & C. Not strictly necessary but it's easier to explain. So if we'd narrowed it down to 4,5 & 6 they would become A,B & C respectively. Putting A on the left side, B on the right and C to one side.
A goes down - A is the heavy coin
B goes down - B is the heavy coin
Neither goes down - C is the heavy coin
Sometimes this puzzle will be written as the odd coin is lighter than the others. The solution is the basically the same. Narrow it down to the group of three by looking for the side that goes up, then to the specific coin, marble or whatever
Step-by-step explanation:
I hope it helps
Answer:
put both weighing on both side of waier and the put al coins one by one and you can clearly see the result