How can you tell if a coin is counterfeit?

Use a scale that is accurate to within 0.01 grams to measure the weight of the coin. Compare your results to that of the genuine coin. If they are significantly off, you may have a counterfeit coin. Use an extremely strong magnet to see if the coin is attracted to it.

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

two weighings
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.

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.

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 do you authenticate coins?

When authenticating coins use a visual inspection, which can immediately show up any blatant fake. Any two-headed coin, for example will not be an error, but a fake. Verify this by holding a genuine coin in one hand and tapping it with another of the same denomination.

How common are counterfeit coins?

Morgan dollar the most counterfeited U.S. coin Among collector gold U.S. coins, 42. 1 percent of the dealers reported counterfeits of the $2.50 gold coin are the most frequently encountered, followed by fakes of $5 gold, 36.2 percent; $20 gold, 33.4 percent; $1 gold, 33.1 percent; and $10 gold, 27.6 percent.

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 minimum number of weighings needed to find the fake coin?

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

How many weighings are necessary to determine if a coin is counterfeit?

How many weighings of a balance are necessary to determine if a coin is counterfeit among eight coins. The counterfeit coin is either heavier or lighter than the other coins. I understand the reas… Stack Exchange Network

How to find the light coin using 2 weightings?

Following these steps you can find the light coin using 2 weightings: You should group the 9 coins into 3 groups each containing 3 coins. If the ones you weigh the same proceed to step 3 with the group you put aside at the step 2. If one of the groups you weigh in step 2 is lighter than the other proceed to step 3 with the lighter group.

How can Nyoman identify the counterfeit coin?

Divide the coins into groups of two each and weigh them again. The group of coins with less weight is chosen. Take one coin each and weigh them again. The coin with less weight is the counterfeit. So, n one step or in maximum three steps,Nyoman can identify the counterfeit coin.

How to determine if a coin is real or fake?

Split the coins into 3 groups – 2 groups with 3 coins each and 1 group with 2 coins. Now put the 2 groups of 3 coins on the scale. Scenario #1: Both groups weigh the same. This means that the counterfeit coin is in the group with 2 coins. So take the 2 coins from that group and use the scale to determine the counterfeit coin.