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Airstud
Topic Author
Posts: 4892
Joined: Wed Nov 29, 2000 11:57 am

### 97% of you will get this wrong...

1 + 4 = 5

2 + 5 = 12

3 + 6 = 21

5 + 8 = ??

I get 37.
Pancakes are delicious.

casinterest
Posts: 12153
Joined: Sat Feb 12, 2005 5:30 am

### Re: 97% of you will get this wrong...

45
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TheF15Ace
Posts: 317
Joined: Fri Mar 04, 2011 10:27 am

### Re: 97% of you will get this wrong...

I got 45

TheFlyingDisk
Posts: 2152
Joined: Mon Jun 09, 2008 12:43 pm

### Re: 97% of you will get this wrong...

It's 34

VSMUT
Posts: 4700
Joined: Mon Aug 08, 2016 11:40 am

### Re: 97% of you will get this wrong...

2 + 5 = 7

3 + 6 = 9

5 + 8 = 13

Seriously, this is basic stuff.

dtw2hyd
Posts: 8472
Joined: Wed Jan 09, 2013 12:11 pm

### Re: 97% of you will get this wrong...

I got 34
All posts are just opinions.

Airstud
Topic Author
Posts: 4892
Joined: Wed Nov 29, 2000 11:57 am

### Re: 97% of you will get this wrong...

Everyone on the Facebook thread seems to have gotten 34 or 45.

I'm the only one out there (I think) who got 37.
Pancakes are delicious.

captaink
Posts: 4010
Joined: Wed May 23, 2001 10:43 am

### Re: 97% of you will get this wrong...

45... When do you show our explanation?
Look Up

Okie
Posts: 4177
Joined: Wed Jul 16, 2003 11:30 am

### Re: 97% of you will get this wrong...

I got 34.

Okie

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

For those who get 45:
Formula is x + y = z, where the result is taken by doing x + (x * y) = z.
Therefore, 1 + 4 = 1 + (1 * 4) = 5. For the last row, 5 + 8 = 5 + (5 * 8) = 45.
This is the ONLY correct answer which works for any x and y values.

For those who get 34:
Formula is x + y = z, where the result is taken by doing x + y + ("result from previous row") = z.
Using that, 5 + 8 = 5 + 8 + 21 = 34. However, there is a row missing for 4 + 7 so you cannot prove that this is the formula.
This DOES NOT work for all x and y values since you need information on previous instances, which negates the premise of a formula.

It's a silly problem, as it's not mathematically correct and the lack of information means it sort of has two answers, as I've shown, if you assume that only the rows presented exist in the problem.
Last edited by ANITIX87 on Mon Mar 13, 2017 2:59 pm, edited 1 time in total.
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casinterest
Posts: 12153
Joined: Sat Feb 12, 2005 5:30 am

### Re: 97% of you will get this wrong...

Airstud wrote:
Everyone on the Facebook thread seems to have gotten 34 or 45.

I'm the only one out there (I think) who got 37.

I could make a strong argument for 37. but it includes making an assumption of the questioners intent on missing a line. So I stand by 45
Where ever you go, there you are.

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

casinterest wrote:
I could make a strong argument for 37. but it includes making an assumption of the questioners intent on missing a line. So I stand by 45

How can you make an argument for 37? I put in the argument for 34, but I can't get 37 no matter what assumptions I make.

If you assume the missing row using the formula for 34, you get:
3 + 6 = 21
4 + 7 = 32
5 + 8 = 45
Last edited by ANITIX87 on Mon Mar 13, 2017 3:06 pm, edited 1 time in total.
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casinterest
Posts: 12153
Joined: Sat Feb 12, 2005 5:30 am

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
casinterest wrote:
I could make a strong argument for 37. but it includes making an assumption of the questioners intent on missing a line. So I stand by 45

How can you make an argument for 37? I put in the argument for 34, but I can't get 37 no matter what assumptions I make.

If you assume that the real equation is N=(x+(y*z)) where y is the line number. so the last line would be 5+(4*8)=37 Like I said, it works out, but it is not logical based on the fact that the missing numbers (4+7) would fall apart if reintroduced.
Where ever you go, there you are.

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

casinterest wrote:
If you assume that the real equation is N=(x+(y*z)) where y is the line number. so the last line would be 5+(4*8)=37 Like I said, it works out, but it is not logical based on the fact that the missing numbers (4+7) would fall apart if reintroduced.

Interesting, my mind never went in that direction. As the row numbers aren't shown, I didn't even entertain the idea of using them. As you say, the logic falls apart when considering the lack of 4 + 7.
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Airstud
Topic Author
Posts: 4892
Joined: Wed Nov 29, 2000 11:57 am

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
casinterest wrote:
I could make a strong argument for 37. but it includes making an assumption of the questioners intent on missing a line. So I stand by 45

How can you make an argument for 37? I put in the argument for 34, but I can't get 37 no matter what assumptions I make.

In each statement; the 2nd operand is multiplied by +1 to said multiplier in the previous statement. Hence 8 → 32.

Edit: casinterest & I clicked submit at the same time :-/
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Tugger
Posts: 10899
Joined: Tue Apr 18, 2006 8:38 am

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
there is a row missing
[...]
It's a silly problem, as it's not mathematically correct and the lack of information means it sort of has two answers, as I've shown, if you assume that only the rows presented exist in the problem.

My issue is with the assumption it is requiring you to make. If one is required to assume that a missing row is to be included in the final answer then the answer could also be "infinity" as you could logically equally assume that every row thereafter should be included.

Tugg
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casinterest
Posts: 12153
Joined: Sat Feb 12, 2005 5:30 am

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
casinterest wrote:
If you assume that the real equation is N=(x+(y*z)) where y is the line number. so the last line would be 5+(4*8)=37 Like I said, it works out, but it is not logical based on the fact that the missing numbers (4+7) would fall apart if reintroduced.

Interesting, my mind never went in that direction. .

If you have ever debugged enough code, you will learn your mind has to examine all the possibilities. Off by one errors are prevalent is software engineering.
Where ever you go, there you are.

SAS A340
Posts: 905
Joined: Fri Jul 28, 2000 5:59 am

### Re: 97% of you will get this wrong...

45 for sure
It's not what u do,it's how u do it!

mham001
Posts: 5745
Joined: Thu Feb 03, 2005 4:52 am

### Re: 97% of you will get this wrong...

45. I just took that online IQ test (139), it was full of these.

JoeCanuck
Posts: 4704
Joined: Mon Dec 19, 2005 3:30 am

### Re: 97% of you will get this wrong...

What the...?

seahawk
Posts: 9762
Joined: Fri May 27, 2005 1:29 am

### Re: 97% of you will get this wrong...

45 as 4+7 is missing.

AirPacific747
Posts: 9718
Joined: Mon May 19, 2008 9:52 am

### Re: 97% of you will get this wrong...

45 for sure. First you multiply the first digit with the second, then you add the first digit to the multiplied number. It didn't seem very difficult as it was easy to pick up the logic using the examples above.

Posts: 10201
Joined: Tue Feb 19, 2008 6:31 pm

### Re: 97% of you will get this wrong...

34
Democrats haven't been this angry since we took away their slaves.

afterburner
Posts: 1459
Joined: Mon Jun 13, 2005 11:38 am

### Re: 97% of you will get this wrong...

Airstud wrote:
Everyone on the Facebook thread seems to have gotten 34 or 45.

I'm the only one out there (I think) who got 37.

37 for me.

Wait. I changed my mind. It's 45.

cjg225
Posts: 2004
Joined: Sun Feb 24, 2013 8:59 pm

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
It's a silly problem, as it's not mathematically correct and the lack of information means it sort of has two answers, as I've shown, if you assume that only the rows presented exist in the problem.

Yeah. I got 45, but the way it's written is just so dumb. Someone trying to be way too cute with a "logic" problem.
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TheFlyingDisk
Posts: 2152
Joined: Mon Jun 09, 2008 12:43 pm

### Re: 97% of you will get this wrong...

ANITIX87 wrote:

For those who get 45:
Formula is x + y = z, where the result is taken by doing x + (x * y) = z.
Therefore, 1 + 4 = 1 + (1 * 4) = 5. For the last row, 5 + 8 = 5 + (5 * 8) = 45.
This is the ONLY correct answer which works for any x and y values.

For those who get 34:
Formula is x + y = z, where the result is taken by doing x + y + ("result from previous row") = z.
Using that, 5 + 8 = 5 + 8 + 21 = 34. However, there is a row missing for 4 + 7 so you cannot prove that this is the formula.
This DOES NOT work for all x and y values since you need information on previous instances, which negates the premise of a formula.

It's a silly problem, as it's not mathematically correct and the lack of information means it sort of has two answers, as I've shown, if you assume that only the rows presented exist in the problem.

4+7? Shouldn't it be 5+7 = 12?

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

TheFlyingDisk wrote:
4+7? Shouldn't it be 5+7 = 12?

No, the last two rows are:

3 + 6 = 21
5 + 8 = ??

The missing row is, therefore, 4 + 7.
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TheFlyingDisk
Posts: 2152
Joined: Mon Jun 09, 2008 12:43 pm

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
TheFlyingDisk wrote:
4+7? Shouldn't it be 5+7 = 12?

No, the last two rows are:

3 + 6 = 21
5 + 8 = ??

The missing row is, therefore, 4 + 7.

But you're assuming that a row is missing. If you assume that there's no missing rows then the answer is correct!

DLFREEBIRD
Posts: 1545
Joined: Thu Mar 05, 2015 6:07 pm

### Re: 97% of you will get this wrong...

i got 45 following a pattern, but since it said 97% of you would get it wrong and almost everyone here says 45
maybe the answer is hiding in plain sight and is just 12?
.

seahawk
Posts: 9762
Joined: Fri May 27, 2005 1:29 am

### Re: 97% of you will get this wrong...

You mean 13, if we assume the line is broken due to the missing 4+7 and starts again.

cjg225
Posts: 2004
Joined: Sun Feb 24, 2013 8:59 pm

### Re: 97% of you will get this wrong...

DLFREEBIRD wrote:
i got 45 following a pattern, but since it said 97% of you would get it wrong and almost everyone here says 45
maybe the answer is hiding in plain sight and is just 12?
.

5 plus 8 is 13.

The interesting thing is that you can be "wrong" no matter what, since the person determining if you're wrong is the person who first presents this problem, because only that person knows whether they want to pull a fast one by saying it's just 5+8=13 or making you read a formula into the entire set that you need to figure out and apply.
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DLFREEBIRD
Posts: 1545
Joined: Thu Mar 05, 2015 6:07 pm

### Re: 97% of you will get this wrong...

lol yes, i meant 13

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

TheFlyingDisk wrote:
But you're assuming that a row is missing. If you assume that there's no missing rows then the answer is correct!

5+7 doesn't appear anywhere in the problem.
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TheFlyingDisk
Posts: 2152
Joined: Mon Jun 09, 2008 12:43 pm

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
TheFlyingDisk wrote:
But you're assuming that a row is missing. If you assume that there's no missing rows then the answer is correct!

5+7 doesn't appear anywhere in the problem.

It's 2+5+5 on the second equation

Raventech
Posts: 208
Joined: Thu Aug 30, 2012 10:25 pm

### Re: 97% of you will get this wrong...

I got 45, I did it based on finding a pattern and fitting am equating to it like one of the guys above, and the "true" equation I saw was n=x*(y+1)

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

TheFlyingDisk wrote:
It's 2+5+5 on the second equation

What? That has nothing to do with what I was saying and with what I thought you were saying. Run through the problem row by row and tell me what you're doing.
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TheFlyingDisk
Posts: 2152
Joined: Mon Jun 09, 2008 12:43 pm

### Re: 97% of you will get this wrong...

ANITIX87 wrote:
TheFlyingDisk wrote:
It's 2+5+5 on the second equation

What? That has nothing to do with what I was saying and with what I thought you were saying. Run through the problem row by row and tell me what you're doing.

It's exactly what you're saying = X + Y + (result from previous row) = Z

1) 1 + 4 + (0) = 5

2) 2 + 5 + (5) = 12

3) 3 + 6 + (12) = 21

4) 5 + 8 + (21) = 34

ANITIX87
Posts: 2998
Joined: Mon Mar 07, 2005 4:52 am

### Re: 97% of you will get this wrong...

TheFlyingDisk wrote:
It's exactly what you're saying = X + Y + (result from previous row) = Z

1) 1 + 4 + (0) = 5

2) 2 + 5 + (5) = 12

3) 3 + 6 + (12) = 21

4) 5 + 8 + (21) = 34

Right, I was saying there's a row for 4+7 missing, and you corrected me to say it should be 5+7.
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Mortyman
Posts: 5879
Joined: Sat Aug 12, 2006 8:26 pm

### Re: 97% of you will get this wrong...

45

Quantos
Posts: 304
Joined: Wed Jan 23, 2013 9:29 pm

### Re: 97% of you will get this wrong...

34 seems correct when you go with the assumption that the values given are the only one in the series. If there is indeed a 4+7 not shown, but implied, then 45 would be the only answer. Pedantic me would say that there is no indication of a missing row, like a "..." or "[...]", so I'm saying 34 is absolutely a correct answer based on the parameters provided!
Quantos,

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Braybuddy
Posts: 6799
Joined: Fri Aug 20, 2004 8:14 pm

### Re: 97% of you will get this wrong...

It's impossible to get a correct answer with a flawed formula, so the 97 per cent are not wrong at all.

seahawk
Posts: 9762
Joined: Fri May 27, 2005 1:29 am

### Re: 97% of you will get this wrong...

Quantos wrote:
34 seems correct when you go with the assumption that the values given are the only one in the series. If there is indeed a 4+7 not shown, but implied, then 45 would be the only answer. Pedantic me would say that there is no indication of a missing row, like a "..." or "[...]", so I'm saying 34 is absolutely a correct answer based on the parameters provided!

13 would make sense, if you believe the line was broken (missing 4+7) and the formula starts new with 5+8

34 would make sense, if you believe the line continues

45 would make sense, if you believe that the missing 4+7 is implied

With this not precise starting formula it is up to the person asking the question to decidce what he thinks is correct.

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