Hard Puzzle 9 Digit Passcode to Open The Door - Tricky Riddle
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As F is 4 or 8 and FGH is divided by 8, GH is divided by 8. As G is an odd number which is not 5, GH = 16, 32 or 72.
As G + H + I is divided by 3, if GH = 16, I should be 2, 5 or 8. But none of them satisfies that I is an odd number and is not 5. So GH = 32 or 72.
It gives H = 2 and C = 6, and G = 3 or 7.
As D + E + F is divided by 3, F = 4, so B = 8
Again, G = 3 or 7. When G = 3, H = 1 (then -A, C- = -7, 9-) or 7 (then -A, C- = -1, 9-. When G = 7, H = 3 (then -A, C- = -1, 9-) or 9 (then -A, C- = -1, 3-. So we get 8 numbers, so we have only to divide ABCDEFG of those 8 numbers by 7.
Date: 2023-11-15
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Comments and reviews: 15
Paras
One more logic we can use to make it even simpler. We can easily reach at below two possibilities:
_ 4 _ 2 5 8 _ 6 _
_ 8 _ 6 5 4 _ 2 _
Now, as first 3 digits are divisible by 3, and middle 3 digits are also be divisible by 3 (to make first 6 digits divisible by 6, last 3 digits will have to be divisible by 3 also. That funnels down to only 4 possibilities which can be reduced to 2 by checking divisibility from 8. Now check these 2 numbers for divisibility of 7 and you are done.
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One more logic we can use to make it even simpler. We can easily reach at below two possibilities:
_ 4 _ 2 5 8 _ 6 _
_ 8 _ 6 5 4 _ 2 _
Now, as first 3 digits are divisible by 3, and middle 3 digits are also be divisible by 3 (to make first 6 digits divisible by 6, last 3 digits will have to be divisible by 3 also. That funnels down to only 4 possibilities which can be reduced to 2 by checking divisibility from 8. Now check these 2 numbers for divisibility of 7 and you are done.
reply
Paras
One more logic we can use to make it even simpler. We can easily reach at below two possibilities:
_ 4 _ 2 5 8 _ 6 _
_ 8 _ 6 5 4 _ 2 _
Now, as first 3 digits are divisible by 3, and middle 3 digits are also be divisible by 3 (to make first 6 digits divisible by 6, last 3 digits will have to be divisible by 3 also. That funnels down to only 4 possibilities which can be reduced to 2 by checking divisibility from 8. Now check these 2 numbers for divisibility of 7 and you are done.
reply
One more logic we can use to make it even simpler. We can easily reach at below two possibilities:
_ 4 _ 2 5 8 _ 6 _
_ 8 _ 6 5 4 _ 2 _
Now, as first 3 digits are divisible by 3, and middle 3 digits are also be divisible by 3 (to make first 6 digits divisible by 6, last 3 digits will have to be divisible by 3 also. That funnels down to only 4 possibilities which can be reduced to 2 by checking divisibility from 8. Now check these 2 numbers for divisibility of 7 and you are done.
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P.
Kinda happy to say that up until [2: 27] or so I deduced myself. I cracked it but I did so with an excel sheet, starting with 5 in the middle, then the 1st digit, then worked my way up, deleting inconsistencies.
Obviously took me far longer but yes! - I solved it and reached the same result.
It won't save me from a ticking bomb but hey at least I wouldn't starve in the room. :)
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Kinda happy to say that up until [2: 27] or so I deduced myself. I cracked it but I did so with an excel sheet, starting with 5 in the middle, then the 1st digit, then worked my way up, deleting inconsistencies.
Obviously took me far longer but yes! - I solved it and reached the same result.
It won't save me from a ticking bomb but hey at least I wouldn't starve in the room. :)
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Rajat
Took me 30 minutes to solve this. First arrived at the conclusion 183654729. Skipped to the end of the video and saw that the first and third digit were interchanged and realized my numerical fault. Counting it as solving though. As usual great puzzle.
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Took me 30 minutes to solve this. First arrived at the conclusion 183654729. Skipped to the end of the video and saw that the first and third digit were interchanged and realized my numerical fault. Counting it as solving though. As usual great puzzle.
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Raj
Good puzzle. You can make it more complicated by saying the digits are 0-9; instead of 1-9; and -0- cannot be used as the left most digit. Now readers have to first select 9 digits from 10 digits. There is a solution with -0- as well-. Try it,
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Good puzzle. You can make it more complicated by saying the digits are 0-9; instead of 1-9; and -0- cannot be used as the left most digit. Now readers have to first select 9 digits from 10 digits. There is a solution with -0- as well-. Try it,
reply
varshit
My first few steps are also the same but I used divisibility rule of 8 instead of using -that if a number is divisible by 8 then it must be divisible by 4 and 2- which gives me 5 possible combinations (472, 496, 672, 872, 896)
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My first few steps are also the same but I used divisibility rule of 8 instead of using -that if a number is divisible by 8 then it must be divisible by 4 and 2- which gives me 5 possible combinations (472, 496, 672, 872, 896)
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Rohan
56 ia divisible by 7 but it doesn't have an odd number at its units place. Then how did u conclude that odd number will come at places which r the units position of number divisible by odd numbers?
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56 ia divisible by 7 but it doesn't have an odd number at its units place. Then how did u conclude that odd number will come at places which r the units position of number divisible by odd numbers?
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Prasun
Answer: Get a car battery with a buck boost converter with copper coils. Complete the circuit and melt the locking mechanism.
Why are you still standing at the lock input console?
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Answer: Get a car battery with a buck boost converter with copper coils. Complete the circuit and melt the locking mechanism.
Why are you still standing at the lock input console?
reply
Ramesh
Whenever8 I feel low or disturbed. I search for something engaging. Especially I love mathematical riddles. This is good one. I solved it in 5mins
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Whenever8 I feel low or disturbed. I search for something engaging. Especially I love mathematical riddles. This is good one. I solved it in 5mins
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Tom
if you just type this question into chatGPT, without any instructions, it writes python code and solves it correctly (brute force) in -10 seconds
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if you just type this question into chatGPT, without any instructions, it writes python code and solves it correctly (brute force) in -10 seconds
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TrueRainsie
An excellent riddle. Solved it halfway through, made a mistake somewhere around divisibility by 7 and erroneously arrived to 147258369.
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An excellent riddle. Solved it halfway through, made a mistake somewhere around divisibility by 7 and erroneously arrived to 147258369.
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Juan
I felt so guilty and dirty checking all possibilities for 7 that it's quite relieving to know it was the only way to go about it.
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I felt so guilty and dirty checking all possibilities for 7 that it's quite relieving to know it was the only way to go about it.
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Mike
I solved it a completely different way and got another answer that is correct so there are more than one passcodes. 123, 606, 729
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I solved it a completely different way and got another answer that is correct so there are more than one passcodes. 123, 606, 729
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RK
7: 50 instead dividing by 7. We can use divisibilty of 8-number formed by last 3 digit must be divisible by 8
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7: 50 instead dividing by 7. We can use divisibilty of 8-number formed by last 3 digit must be divisible by 8
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Tanishq
you always say that you'll post new riddles every week, but you never do that. kindly be more regular.
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you always say that you'll post new riddles every week, but you never do that. kindly be more regular.
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