Suppose you had eight billiard balls, one of them is slightly heavier, but the only way to tell is by putting it on a scale against the others. What's the fewest number of times you'd have to use the scale to find the heavier ball?
This is a nice one....
Give it a shot to who wants to try out and if anyone wants the answer mail me..
From India, Mumbai
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This is a nice one....
Give it a shot to who wants to try out and if anyone wants the answer mail me..
From India, Mumbai
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Dear Trishant,
The answer is 3. Put 4 balls on each scale, one scale will be heavier. Take the balls on the heavier scale and then put 2 on each side; again, one will be heavier. Take these 2 balls and put them on separate scales. You will then know which ball is heavier.
From India, Pune
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43The answer is 3. Put 4 balls on each scale, one scale will be heavier. Take the balls on the heavier scale and then put 2 on each side; again, one will be heavier. Take these 2 balls and put them on separate scales. You will then know which ball is heavier.
From India, Pune
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Dear Trishant,
The answer is 2.
Step 1: Put 3 balls on each scale, then you will have 2 balls left over in your hand. If the scale shows equal weight, then go to step 2A; otherwise, go to step 2B.
Step 2A: The scale is showing equal weight; therefore, the heavier ball will be in your hand. Put both balls (which you have in your hand) on each scale, and you will get the heavier one.
Step 2B: Take the balls from the heavier scale and put 1 ball in each scale; then you will have one ball left over in your hand. If the scale shows equal weight, then the heavier ball will be in your hand; otherwise, the scale will show the heavier one.
Regards
From United States, Cincinnati
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The answer is 2.
Step 1: Put 3 balls on each scale, then you will have 2 balls left over in your hand. If the scale shows equal weight, then go to step 2A; otherwise, go to step 2B.
Step 2A: The scale is showing equal weight; therefore, the heavier ball will be in your hand. Put both balls (which you have in your hand) on each scale, and you will get the heavier one.
Step 2B: Take the balls from the heavier scale and put 1 ball in each scale; then you will have one ball left over in your hand. If the scale shows equal weight, then the heavier ball will be in your hand; otherwise, the scale will show the heavier one.
Regards
From United States, Cincinnati
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Nice answer, Adiiti. Thanks to everyone else who liked the post. I'm going to post others I know may or may not be as good.
Regards,
Trishant
Here's another one to imagine: you have two completely unmarked bottles, one holding exactly 3 liters and the other 5 liters, with an ample amount of water. Your task is to fill exactly 4 liters in one of the bottles.
It's evident that it would be in the 5-liter bottle. How would you do it?
Hint: You can fill and empty the bottles as much as you want.
From India, Mumbai
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Regards,
Trishant
Here's another one to imagine: you have two completely unmarked bottles, one holding exactly 3 liters and the other 5 liters, with an ample amount of water. Your task is to fill exactly 4 liters in one of the bottles.
It's evident that it would be in the 5-liter bottle. How would you do it?
Hint: You can fill and empty the bottles as much as you want.
From India, Mumbai
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Simple... Just pour out the water from both the bottles until it bocome exact half, then you will have 1.5 and 2.5 litres in both the bottles. Now you can fill 1.5 litter in another bottel. Regards
From United States, Cincinnati
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From United States, Cincinnati
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Dear Aditi,
Actually, that's not the answer. You need to fill and empty both the jars a particular number of times. I have no patience to write down all the steps. Check out the attachment for something similar.
Ok, here it is. Fill 5 liters and empty it into 3 liters, so 5 liters will have 2 liters and 3 liters will have 3 liters. Then empty 3 liters and transfer 2 liters from 5 liters into it. Now, 5 liters is empty, and 3 liters has 2 liters in it. Next, fill up the 5 liters and transfer the content to the 3 liters without spilling. What happens is the 3 liters already has 2 liters of water in it, so only 1 liter goes into it. And 4 liters of water remain in the 5-liter bottle.
Hope you understand.
From India, Pune
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Actually, that's not the answer. You need to fill and empty both the jars a particular number of times. I have no patience to write down all the steps. Check out the attachment for something similar.
Ok, here it is. Fill 5 liters and empty it into 3 liters, so 5 liters will have 2 liters and 3 liters will have 3 liters. Then empty 3 liters and transfer 2 liters from 5 liters into it. Now, 5 liters is empty, and 3 liters has 2 liters in it. Next, fill up the 5 liters and transfer the content to the 3 liters without spilling. What happens is the 3 liters already has 2 liters of water in it, so only 1 liter goes into it. And 4 liters of water remain in the 5-liter bottle.
Hope you understand.
From India, Pune
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To fill exactly 4 litres in one bottle - Fill the 3-litre bottle full, then transfer the water into the 5-litre bottle. Again, fill the 3-litre bottle full and carefully transfer the water into the 5-litre bottle. Not all the water will go inside the 5-litre bottle, i.e., 1 litre will remain in the 3-litre bottle. Throw the water out from the 5-litre bottle. Pour the 1 litre that is in the 3-litre bottle. Fill the 3-litre can full with water. Pour the 3 litres of water into the 5-litre bottle, which already contains 1 litre of water. In this way, you will have exactly 4 litres of water in the 5-litre bottle.
From India, Hyderabad
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From India, Hyderabad
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how do u knw u have exact half... you can never be sure that its exactly half... once u feel u have exact 4litres it will measured and has to be exact 4litres not a ml here and there.. think again..
From India, Mumbai
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From India, Mumbai
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Nice answers, people...
Next one...
Imagine you are stranded on an island and you have only 6 cm of gold and a knife that can cut the gold only twice, and after that, the knife is also useless. Then a man comes to you and offers you unlimited food every day, each day for one cm of gold. For example, you give 1 cm on the 1st day, 2 cm total on the 2nd, 3 cm on the 3rd, and so on until you end up giving all the 6 cm on the last day.
Now there are 2 questions:
1. In what proportions will you cut the gold?
2. How will you manage to give the gold as you can be fed each day? (P.S: There's nothing like giving any advance amounts of gold or any loan basis.)
Hint: The give-and-take policy also works here.
From India, Mumbai
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Next one...
Imagine you are stranded on an island and you have only 6 cm of gold and a knife that can cut the gold only twice, and after that, the knife is also useless. Then a man comes to you and offers you unlimited food every day, each day for one cm of gold. For example, you give 1 cm on the 1st day, 2 cm total on the 2nd, 3 cm on the 3rd, and so on until you end up giving all the 6 cm on the last day.
Now there are 2 questions:
1. In what proportions will you cut the gold?
2. How will you manage to give the gold as you can be fed each day? (P.S: There's nothing like giving any advance amounts of gold or any loan basis.)
Hint: The give-and-take policy also works here.
From India, Mumbai
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Simple. First, fill up the 5-liter bottle and from that fill the 3-liter bottle fully. You have 2 liters remaining in the 5-liter bottle.
Next step is to empty the 3-liter bottle. Pour the 2 liters remaining in the 5-liter bottle into the 3-liter bottle. Now again fill the 5-liter bottle fully.
Finally, pour water from the 5-liter bottle into the 3-liter bottle. Since the 3-liter bottle already has 2 liters of water, it can take only 1 more liter. That means there are 4 liters left in the 5-liter bottle.
From India, Kochi
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Next step is to empty the 3-liter bottle. Pour the 2 liters remaining in the 5-liter bottle into the 3-liter bottle. Now again fill the 5-liter bottle fully.
Finally, pour water from the 5-liter bottle into the 3-liter bottle. Since the 3-liter bottle already has 2 liters of water, it can take only 1 more liter. That means there are 4 liters left in the 5-liter bottle.
From India, Kochi
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