How many weighings of a balance scale are needed to find a counterfeit coin among 12 coins?

How many weighings of a balance scale are needed to find a counterfeit coin among 12 coins?

Hence the minimum number of weighings required to find the fake coin using a two pan balance is 3. Start by numbering the coins 1.. 12. put 1,2,3,4 on the left scale, 5,6,7,8 on the right.

How many weighings of a balance scale are needed to find a counterfeit coin among eight coins if the counterfeit coin is either heavier or lighter than the others?

two weighings are needed. separate into three groups (3,3,2) put three on each side of scale, if sides balance then place two remaining coins on either side of scale to see which is heavier.

Can you find the counterfeit coin using just two weighings?

Solution 1 Take any two of them and put them on the opposite cups of the scale. If they weigh the same, it is the third coin in the lighter group that is fake; if they do not weigh the same, the lighter one is the fake. Thus the problem is solvable in two weighings.

What is the coin riddle?

No matter what combination of coins you choose, you will suddenly have a number of silver-side-up coins that’s equal to whatever is left in the pile. If every coin you pulled was originally gold-side-up, flipping them would give you 20 more silver-side-up coins.

How many weighing Do you need to find the counterfeit coin among 81 coins?

So, with 4 weighings, you can do upto 81 coins this method. You weigh the two 27 coin ones. If they are not equal, you pick the one that weighs the least, if they are equal, then you grab the group of 26 that you didn’t weigh. Set aside the other two groups as the counterfeit coin are not there.

What is the minimum number of weighings needed to find the fake coin?

two weighings
By the way, two weighings is the smallest number of weighings that guar- antee finding the fake coin.

What is the meaning of counterfeit goods?

Counterfeit products are fakes or unauthorized replicas of the real product. Counterfeit products are often produced with the intent to take advantage of the superior value of the imitated product.

How many equal coins are there in the pile?

There is a pile of 12 coins, all of equal size, but only 11 are of equal weight. Can you find the unequal coin and determine if it is heavier or lighter, in 3 weighings? – Quora There is a pile of 12 coins, all of equal size, but only 11 are of equal weight.

How do you find the unequal weight of 12 coins?

Divide this 12 coins in 3 piles of 4 coins name them A,B and C respectively. Now take 1 coin from D and 1 from E and place on A and B and continue till both of them are unequal. Now the last coins which you added on the both piles A and B one of them is either heavier or lighter. We can find the unequal weighted coin by 2 or 3 weighing.

How do you find the odd coin among 12 coins?

Given that a coin is heavier, verify that 3 trials are sufficient to find the odd coin among 12 coins, because 3 2 < 12 < 3 3. We are given 4 coins, out of which only one coin may be defective. We don’t know, whether all coins are genuine or any defective one is present.

Can two coins have the same weight but different weights?

They can have same weight or one of them can be heavier. Lets divide this up into two different cases: Case 1: equal weight: In this case, we know that the unequal coin is among the coins that were on neither side of the balance. We also know, that all the coins we weighted are equal.