Can you solve the vampire hunter riddle? - Dan Finkel
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Date: 2020-08-22
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Comments and reviews: 10
Renslay
I found the solution with a slightly different approach.
Instead of bouncing lights, I assumed the light goes in a straight pass, and the room itself has infinite copies along both the x and y axis. Each time the light touches the wall, it does not bounce, but goes straight through into a copy of the room - but this room is mirrored along that wall.
Now, at some time, the light reaches the TOP-RIGHT corner of some room. The question is the orientation of this room: is it mirrored along the x axis, y axis, neither, both?
Assume the light travelled K rooms along the x axis, and L rooms along the y axis. Since we arrived at a corner, 78L = 49K. We need an integer solution for K and L. One trivial solution is K = 78, L = 49.
Each time the light travels through a room, it got mirrored. So, even number of rooms means it is mirrored along that axis, and odd number means the room is not mirrored compared to the original one.
x axis -> K = 78 -> even -> not mirrored -> the orner is on the RIGHT side.
y axis -> L = 49 -> odd -> mirrored case -> the corner is on the BOTTOM side.
Solution: bottom right (SE) corner.
PS: unlike the proof seen on the video, my solution also guarantees that the light does not bounces back to the SW corner.
reply
I found the solution with a slightly different approach.
Instead of bouncing lights, I assumed the light goes in a straight pass, and the room itself has infinite copies along both the x and y axis. Each time the light touches the wall, it does not bounce, but goes straight through into a copy of the room - but this room is mirrored along that wall.
Now, at some time, the light reaches the TOP-RIGHT corner of some room. The question is the orientation of this room: is it mirrored along the x axis, y axis, neither, both?
Assume the light travelled K rooms along the x axis, and L rooms along the y axis. Since we arrived at a corner, 78L = 49K. We need an integer solution for K and L. One trivial solution is K = 78, L = 49.
Each time the light travels through a room, it got mirrored. So, even number of rooms means it is mirrored along that axis, and odd number means the room is not mirrored compared to the original one.
x axis -> K = 78 -> even -> not mirrored -> the orner is on the RIGHT side.
y axis -> L = 49 -> odd -> mirrored case -> the corner is on the BOTTOM side.
Solution: bottom right (SE) corner.
PS: unlike the proof seen on the video, my solution also guarantees that the light does not bounces back to the SW corner.
reply
Ihaia
you wouldn't need any diffusers in this experiment.
Since the walls are metallic (and obiously not blocked by wooden coffins as earlier stated, then it doesn't matter which corner the light hits. By the time the supposed light hits the SE corner, it should technically bounce all the way back again until it exits the SW corner. With the number of reflections that take place in that time, it'll be impossible for anyone to avoid those light beams.
This experiment also assumes that every single vampire will open their coffins at the exact same time the sun passes the determined angle - all they'd need to do is open the coffin slightly, realize that there's sunlight and it's burning them, close the coffin and wait for ONE MINUTE before the sun's angle gets too steep for that person, before their experiment becomes invalid.
Me: 1
Ted-ed: 19, 999
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you wouldn't need any diffusers in this experiment.
Since the walls are metallic (and obiously not blocked by wooden coffins as earlier stated, then it doesn't matter which corner the light hits. By the time the supposed light hits the SE corner, it should technically bounce all the way back again until it exits the SW corner. With the number of reflections that take place in that time, it'll be impossible for anyone to avoid those light beams.
This experiment also assumes that every single vampire will open their coffins at the exact same time the sun passes the determined angle - all they'd need to do is open the coffin slightly, realize that there's sunlight and it's burning them, close the coffin and wait for ONE MINUTE before the sun's angle gets too steep for that person, before their experiment becomes invalid.
Me: 1
Ted-ed: 19, 999
reply
Bhaskar
My solution:
Notice that 49 and 78 are coprime hence we know directly that it will travel the height 78 times and width 49 times, hence the point will be in the same horizontal line and opposite vertical line form the X and Y axis drawn from the source respectively. But the solution in the video is much cleverer and I absolutely loved it because the solution is almost instantaneous( Given the fact that the beam will not end up in the Source and it will end in of the three holes)
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My solution:
Notice that 49 and 78 are coprime hence we know directly that it will travel the height 78 times and width 49 times, hence the point will be in the same horizontal line and opposite vertical line form the X and Y axis drawn from the source respectively. But the solution in the video is much cleverer and I absolutely loved it because the solution is almost instantaneous( Given the fact that the beam will not end up in the Source and it will end in of the three holes)
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Babli
I would just wait for a moonlight night in which moon will be perfectly visible and then i would set a bait so that every vampire can come out of the castle and then when they all will be outside the castle
I will tell them that how science works and how moonlight is just a reflection of sunrays
Kaboommm! They all dead now
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I would just wait for a moonlight night in which moon will be perfectly visible and then i would set a bait so that every vampire can come out of the castle and then when they all will be outside the castle
I will tell them that how science works and how moonlight is just a reflection of sunrays
Kaboommm! They all dead now
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Ashila-Alisha-
No one:
Not a single freaking soul:
Ted-Ed: We're going to make amazing videos and riddles. Oh right, their impossible to solve unless you know all sorts of math. One more thing! There are always alternative solutions to the riddles that we won't explain!
(JK great job Ted-Ed)
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No one:
Not a single freaking soul:
Ted-Ed: We're going to make amazing videos and riddles. Oh right, their impossible to solve unless you know all sorts of math. One more thing! There are always alternative solutions to the riddles that we won't explain!
(JK great job Ted-Ed)
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Spoookus
So the chamber can be flooded with sunlight as you have just clearly shown, the whole chamber was flooded with sunlight from the beam entering the room anyways. The diffuser was not necessary in the slightest
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So the chamber can be flooded with sunlight as you have just clearly shown, the whole chamber was flooded with sunlight from the beam entering the room anyways. The diffuser was not necessary in the slightest
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Anushka
This riddle has the easiest Explanation. Just use the basics of right-angled Isosceles triangle. It will not bounce off many times. In fact only 1 time. From point (49, 49) in his coordinate system.
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This riddle has the easiest Explanation. Just use the basics of right-angled Isosceles triangle. It will not bounce off many times. In fact only 1 time. From point (49, 49) in his coordinate system.
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perigin3
I feel like the fact that the size of the room isn't included in the pause here screen is a bit misleading, as you need to know it to know that you'll never hit those corners
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I feel like the fact that the size of the room isn't included in the pause here screen is a bit misleading, as you need to know it to know that you'll never hit those corners
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Mr. Magnetix
drawing a line is probably more efficient than covering the room in a grid, filling it with with points and then doing some calcualtions.
especially for my species
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drawing a line is probably more efficient than covering the room in a grid, filling it with with points and then doing some calcualtions.
especially for my species
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РОГОФОС
if light bounces through the entire room before hitting the diffuser doesnt it makes light fill this room even before it hit diffuser, making diffuser pointless?
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if light bounces through the entire room before hitting the diffuser doesnt it makes light fill this room even before it hit diffuser, making diffuser pointless?
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