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Halloween = Christmas?
Trick
Trick brain teasers appear difficult at first, but they have a trick that makes them really easy.Trick
When does Oct 31 = Dec 25 make sense?
Hint
Think about math and what Oct and Dec stand for.Answer
When you use base 8 (Oct) and base 10 (Dec).Hide Hint Show Hint Hide Answer Show Answer
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Comments
Totally don't get this one...
Very good. 31(octal) = 3x8 + 1 = 25!
taht made no sence! tri again
umm...huh?? dont get this one at all.
Sorry, don't get it
if anyone does not know what this teaser means please say so in a comment thanks
Yep- I don't get it.
Okay, do you guys know what a base is? Liek Base 2, Base 3, etc. If you do, skip to the next pargraph. Base 10 is the system of numbers we use it is what makes 9x9=81. The 8 in 81 stands for 8x10, and the 1 stands for 1x1. Thus, 81 is 8x10+1x1. In Base 10, there are 10 digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Now let's take Base 9. There are 9 digits: 0, 1, 2, 3, 4, 5, 6, 7, and 8. So, if you wanted to change the number 72 (which is written in Base 10) to Base 9: it would become 80. Becuase the last digit represents that digit times 1. The first digit represents that digit times 9. So it would be 8x9+0x1. Thus, 72. It is the same with binary. Binary is Base 2. So if you wanted to change Base 10 "27" to Base 2 (which uses two digits: 0 and 1) you would write 11011. The first digit represents that many 16's, the second digit represnts that many 8's, the third digit represents that many 4's, the fourth digit represents tjhat many 2's, the fifth digit represents that many 1's. So for Base 2 '11011'; to change it to Base 10 (normal) you need to do simple math: 1 tmes 16 plus 1 times 8 plus 0 times 4 plus 1 times 2 plus 1 times 1. 16+8+0+2+1 equals 27, which is right.
So, with that explanation out of the way... OCT is short for octal meaning Base 8. So 31 is in Base 8. To change base 8 '31' to base 10;; we need to apply the same principles. The last digit is that many 8^0's. The second to last digit is that many 8^1's. So the 3 represents 3 times 8^1 and the 1 represents 1 time 8^0. So, it is 3x8 plus 1x0. This is 25 in base 10. DEC 25 means Base 10 '25'. Since Base 10 is normal, we could write DEC 25 as 25. Since we know OCT 31= normal 25, and DEC is 25, we know they are equal.
Since that explanation is pretty bad (gimme a break, I'm a high school junior) jsut google Bases or put it into wikipedia and they'll explain it better.
To the author of the teaser- GREAT JOB. I loved it, I was really happy when I got it, but it took me 5-10 minutes. Good job, and make some more!!!
So, with that explanation out of the way... OCT is short for octal meaning Base 8. So 31 is in Base 8. To change base 8 '31' to base 10;; we need to apply the same principles. The last digit is that many 8^0's. The second to last digit is that many 8^1's. So the 3 represents 3 times 8^1 and the 1 represents 1 time 8^0. So, it is 3x8 plus 1x0. This is 25 in base 10. DEC 25 means Base 10 '25'. Since Base 10 is normal, we could write DEC 25 as 25. Since we know OCT 31= normal 25, and DEC is 25, we know they are equal.
Since that explanation is pretty bad (gimme a break, I'm a high school junior) jsut google Bases or put it into wikipedia and they'll explain it better.
To the author of the teaser- GREAT JOB. I loved it, I was really happy when I got it, but it took me 5-10 minutes. Good job, and make some more!!!
well at least that wasnt complicated
i know it is hard to say but
sorry that i didn't explain what base 8 and 10 are but i will say now that they are:
numbers that are for example base 10 that we use all the time has units, tens and hundreds but in base 8 there are eights, sixteenths and sixty-fourths or to make it easier we can wright it as
10 1
2 5
for the base 10 and
8 1
3 1
in base 8 all you have to do is multiply the top and bottom numbers of each column and add the two numbers together and you will get the number if it was in base 10!!!
hope that helps you all pps:
sorry that i didn't explain what base 8 and 10 are but i will say now that they are:
numbers that are for example base 10 that we use all the time has units, tens and hundreds but in base 8 there are eights, sixteenths and sixty-fourths or to make it easier we can wright it as
10 1
2 5
for the base 10 and
8 1
3 1
in base 8 all you have to do is multiply the top and bottom numbers of each column and add the two numbers together and you will get the number if it was in base 10!!!
hope that helps you all pps:
This was very easy for me, but I can convert bases without a problem...but it was still awsome; I'll have to see if it can stump my Calculus teacher or not. Good job!
I was always lousy at arithmatic
but the teaser was a good one, for the ones who understand it lol
but the teaser was a good one, for the ones who understand it lol
say what
Very good teaser!
It would be helpful to the masses to give add explanation to your answer. Might open some people's eyes to the WONDERS of Base 8, wow!
It would be helpful to the masses to give add explanation to your answer. Might open some people's eyes to the WONDERS of Base 8, wow!
Nice. Still wasn't thinking Oct ( and Dec (10) when I saw the hint. I was thinking October (10th month) and December (12th month). So, I took Oct 31 to mean 10x31 and Dec 25 as 12x25, but that came up a little short. Good job!
The is supposed to be an 8 in parenthesis....Didn't realize it would turn into that. Maybe that makes my comment a little more clear.
Hmm, way to late for me to decipher and think! Thanks for the entertainment and the fogged brain!! I used to know this stuff??
WOW! I never thought of that!
Shouldn't this be in the Math section?
Shouldn't this be in the Math section?
Yay, I got it! Too bad it was only because that's what we're studying in school right now!
oh my!
hmmmm, I was looking for a trick or something! Ha was I wrong!
I knew it was something to do with Oct being 8 and Dec being 10, but the maths part stumped my brain. I still feel like I won though
So we're supposed to be mega genii???
that stuff went waayyyyy over my head reading it.
Yep... this is getting favorited.
Very nice! I'll have to remember this one!
Very nice! I'll have to remember this one!
I think it should be in the math section as it has more to do with math than a trick.
Math trivia?
Math trivia?
I agree, definitely should have been a math question! There was no real trick...
WOW brilliant teaser!!
loved it
loved it
Good teaser, but I must be falling asleep. I didn't get it untill I read the answer.
Very Clever.
Good Night
Very Clever.
Good Night
my reason for it being put in the trick section is that it is sortof a trick with what oct and dec means sorry if this confuses anyone
ya'all are too brainy for this old lady.
it is hard. ay
i get it! Im into maths
i am glad some people understand it i do
If your computer uses windows, try this: Open the calculator (it should be under accessories). Set it for scientific view, if it is not already. Under the number screen on the left-hand side you'll see these choices: Hex, Dec, Oct, and Bin. It should already be set for Dec. Enter 25. Click to choose Oct. The number will change to 31. So Dec 25=Oct 31! (This may work on Mac's, too. I've never had one, so I don't know if it has a calculator function.)
yes i was thinking in posting that but it seemed pointless as people already understand it but i think i was wrong
Wow that was one of the most complicated teasers i've ever seen
yeah i love maths
I'll nod and pretend to understand. From the other comments, it seems like a good teaser. I'll just return to this teaser when I understand.
that is cool, that it works out that way!
yeah. i found i quite amazing when i found out about it too!
Thats a toughie...
Good job!!!
Good job!!!
I found it quite easy, actually, but that's just me. The hint gave it away, sort of. GREAT TEASER!!!
For those who don't get it, please be polite when you are stating that. Not mentioning any names or anything...
For those who don't get it, please be polite when you are stating that. Not mentioning any names or anything...
*read this with an attitude please*
whoa, whoa, whoa li'l boy. Say what now??? This ain't got nothin' on my trick teasa. So get your little piece of math outta my face before I have to turn on my "Oh no, you did-n't".
whoa, whoa, whoa li'l boy. Say what now??? This ain't got nothin' on my trick teasa. So get your little piece of math outta my face before I have to turn on my "Oh no, you did-n't".
Sorry if I offended you it's just you shouldn't have this in trick because it does not have a trick that makes it easy. This would be a good math teaser, though.
Also they both equal Nov. 27, which sometimes is thanksgiving!
This is one of my favorite teasers to throw at computer science collegues. I just word it as "How does Holloween equal Christmas" and let them think about it. I'm really happy to see it is in the Braingle collection.
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