How many weighings of a balance scale are needed to find a counterfeit coin among 12 coins if the counterfeit coin is lighter than the others?
3 weighings
Overall we need 3 weighings to trace the odd coin.
What is the fake coin problem?
What is Fake Coin Problem? Fake coin problem is an interesting problem in which we have to find a fake coin out of a number of coins, which is assumed to be lighter than the real coins using just a balance scale, which can be used to compare the weights of two piles of coins.
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.
Are copy coins legal?
Are replicas U.S. legal tender? No, replicas are not legal tender. Under the U.S. Constitution, only the federal government can mint legal tender coins. Replicas of U.S. coins cannot be exchanged as legal tender or used as money.
What if my coin says copy?
A copy coin is a coin that uses a design from a popular coin. These coins may or may not be made of precious metals, and the intention here is to replicate bullion or rare gold coins. They will typically indicate that they are copy coins, so that they do not deceive consumers.
How do I get out of scale chamber?
How to Beat the Scale Chamber. You need to place two gold statues and a pot from the room, onto the scale, then flash the switch. Now, take a gold statue off and flash again. Now place four gold statues to clear the room.
What is the minimum number of weighings needed to identify the fake coin?
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 a copy coin?
What are fake coins made of?
Most of the counterfeit coins are made from a base metal, like tungsten, that is plated with a little gold. This way it will pass the acid test that indicates gold. If it is well-made, the fake will weigh the same as the genuine piece, making it even harder to spot.
How do you calculate coins?
Multiply the weight of the coin by the percentage “fineness” of the coin (the percentage of the coin that is gold or silver). This will establish how much of the precious metal you have to sell. Multiply the result of the first calculation by the current price of the precious metal in the coin.
How many coins are in a coin jar?
💰 The jar is clear so that you can watch as your money accumulates. Holds about 800-1000 coins total. 💰 Ideal for children as it is made of durable plastic that won’t break if dropped.
Are copy coins valuable?
Replica coins are not made of the same composition as genuine U.S. coins. While they look similar, they are made of gold or silver plate. For this reason, they are much cheaper than U.S. coinage or bullion.
Overall we need 3 weighings to trace the odd coin.
What is the minimum number of weighings needed to identify the stack with the fake coins?
one weighing
What is the minimum number of weighings needed to identify which stack contains the fake coins? Explain. Author’s hint: The answer is that one weighing is enough.
How many times would you need to use the scale if you had 3 marbles?
You are allowed to use the scales three times if you wish, but no more. Note that the unusual marble may be heavier or lighter than the others. You are asked to both identify it and determine whether it is heavy or light.
How do you solve the 12 coin problem?
On the second weighing of 1,2,5 v 3,4,6, if 1,2,5 goes down again, then either 1 or 2 is the counterfeit and it is heavy OR 6 is the counterfeit and it is light. So, if on the third weighing 1v2 is equal, then 6 is the counterfeit and it is light. This is now the complete answer to the 12 coin problem.
How will you weigh 9 marbles 3 times on a balance scale to find the heaviest one?
Our Solution: Divide the 9 balls into 3 groups of 3. Compare the weight of two of those groups. The heavier group should then be obvious, it will either tip the scales, or, if the scales stay balanced, then it is the group you didn’t include.
How many marbles do you need to balance the scale?
You are allowed to use the balance scale exactly 3 times to identify which of the 12 marbles is irregular AND determine whether it is heavier or lighter than normal.”