Math riddle

[USNRET]

Lots of more smarter people than me here. I see a pattern that is not identified by notation but led me to assume that the pattern should continue and therefore 4+7 thru 7+10 is to be calculated where the answer to 8+11 would be 96. Others do not make that assumption and answer 40. Both could be correct based on assumption of pattern continuation with / without proper annotation.

 

What say you?

 

[BigStewMan]

coincidently, i ran across this riddle on saturday. 96 makes more sense to me; but, there is a pattern to reach both 96 and 40.

[mungkiman]

I see 2 different patterns that result in 96.

[dtr20]

I get 40

[wvu80]

The answer is 52.

 

First set: Multiply the second column by 1, add the first column.

 

Second set: Multiply the second column by 2, add the first column.

 

Third set: Multiply the second column by 3, add the first column.

 

Fourth set: Multiply the second column by 4, add the first column.  8 + (4x11=44)  = 52

[mungkiman]

13 minutes ago, wvu80 said:

The answer is 52.

 

First set: Multiply the second column by 1, add the first column.

 

Second set: Multiply the second column by 2, add the first column.

 

Third set: Multiply the second column by 3, add the first column.

 

Fourth set: Multiply the second column by 4, add the first column.  8 + (4x11=44)  = 52

 

Your reasoning actually equals 96. Look for the Eighth set.

 

[wvu80]

Oh, I see.  I thought we were solving for the fourth set, not the eighth set.

 

Read the instructions. 

[Quiet_Hollow]

The answer is 19.

 

The second and third expressions are false, unless we're on Pluto....drinking scotch with JB.

[Jeff Matthews]

40.

[RockOn4Klipsch]

3 of the patterns I see all equate to 96.

Addition:

1+4=5

2+5=7(+sum above 5=12)

3+6=9(+sum above(12) =21)

4+7=32

5+8=45

6+9=60

7+10=77

8+11=96

 

Multiplication and addition:

Second column multiply by first column plus column 1.

1+4=5              4x1+1=5

2+5=7              5x2+2=12

3+6=9              6x3+3=21

8+11=96         11x8+8=96

[Jeff Matthews]

I just now caught the confusion.  There is no indication that 4 + 7 through 7 + 10 should be part of the problem.  There is no ellipsis to indicate, "and so on..."  There is no instruction to fill in the gap.  

 

There is only 1 answer.  40.

[Jeff Matthews]

1 hour ago, RockOn4Klipsch said:

Multiplication and addition:

Second column multiply by first column plus column 1.

1+4=5              4x1+1=5

2+5=7              5x2+2=12

3+6=9              6x3+3=21

8+11=96         11x8+8=96

Interesting, but not intended.

[babadono]

Good thing real numbers and the real world don't work this way

[RockOn4Klipsch]

So it seems that the only time the sum of 96 represents itself is if we assume that the equations 4+7 through 7+10 need some type of equation.

The number 40 represents itself only when solved for the currently present equations.

I kept missing the sum of 40, even when looking for it as I was continuing to search and solve for the equations that weren't present.

 

Either way, I suppose there isn't an actual correct corresponding sum as it's only a matter of locating a pattern in which 'works".

 

[DrWho]

There are fundamental principals in math that force this to be an invalid number set. Finding a pattern within a partial set does not make that pattern logical. That's called confirmation bias, and is a form of illogical thinking.

 

Math is the language of logic and "riddles" like this violate such basic (yet profound) ideas that have me concluding "arrogant ignorance" as my final answer.

 

Btw, I'd love to be shown wrong. I went through and analyzed this giving the numbers arbitrary weighting and assuming an arbitrary base system but it still is invalid.

 

If you want your fancy patterns to be the answer, then you need to modify the notation of the riddle statement.

 

[Jeff Matthews]

9 minutes ago, DrWho said:

There are fundamental principals in math that force this to be an invalid number set. Finding a pattern within a partial set does not make that pattern logical. That's called confirmation bias, and is a form of illogical thinking.

 

Math is the language of logic and "riddles" like this violate such basic (yet profound) ideas that have me concluding "arrogant ignorance" as my final answer.

 

Btw, I'd love to be shown wrong. I went through and analyzed this giving the numbers arbitrary weighting and assuming an arbitrary base system but it still is invalid.

 

If you want your fancy patterns to be the answer, then you need to modify the notation of the riddle statement.

 

Your points are a bit too obscure.  I see nothing wrong with the question as a test of one's ability to spot patterns.  

 

In math, we are taught to extrapolate.  That's what this process involves.

 

2, 4, 6, 8.... 

 

10, right?  

[DrWho]

Your notation in the way you presented your 2,4,6 pattern is very different.

 

You might see it as being anal retentive, but it's the sloppiness in notation that causes so many problems for people trying to learn math.

 

It's not wisdam to interchonge o's and a's even thaugh it's understondoble to a humon.

 

See how awkward that looks? To a "genius" that's how the riddle looks....except it looks so awkward it implies a completely different meaning.

[Jeff Matthews]

20 minutes ago, DrWho said:

Your notation in the way you presented your 2,4,6 pattern is very different.

 

You might see it as being anal retentive, but it's the sloppiness in notation that causes so many problems for people trying to learn math.

 

It's not wisdam to interchonge o's and a's even thaugh it's understondoble to a humon.

 

See how awkward that looks? To a "genius" that's how the riddle looks....except it looks so awkward it implies a completely different meaning.

Perhaps it is awkward in your example, which involves proper spelling.  Nevertheless, you have exposed a pattern for all to see, and the ability to spot patterns is very important in other applications.  So what if it's useless as a grammar lesson?  How about this, instead?

 

A car is traveling at a constant velocity.  After 2 minutes, it has traveled 1 mile.  After 4 minutes, it has driven a total of 2 miles.  How many minutes will have elapsed when the care has traveled 3 miles?

 

Edit:  Somebody had to do some pretty decent observing to come up with pi * r^2.  It just didn't come as dumb luck.

 

[Thaddeus Smith]

16 hours ago, Quiet_Hollow said:

The answer is 19.

 

The second and third expressions are false, unless we're on Pluto....drinking scotch with JB.

This. Precisely this.

[DrWho]

I'm not sure I'm tracking with you Jeff.

 

Just think through the mathematical grammar of the riddle....

 

It starts with 1 + 4 = 5. Okay, that's easy for everyone to understand.

The next line starts with 2 + 5 = 12. Okay, normally we expect 7 in a Base 10 system. The riddle doesn't have 7 as the result, so now the logical process is to reevaluate our assumptions. Perhaps it's not a Base 10 system? A quick check reveals that a Base 6 system gets the closest, but 2 + 5 = 11 in Base 6, not 12.

 

Okay, so maybe the numerical symbols have different weighting? At this point I would pause and point out that this is really digging deep into "assumptions" and there isn't much value in changing the weighting of numerical symbols. However, it is a riddle and we must at least assume proper grammar, right? Isn't grammar usually at the foundation of most riddles? Unfortunately the symbol for 2 exists in both sides of the equation, which poses certain limitations on how addition works. To end up with the same least significant digit, you must add by an integer count of the Base....Base 5 doesn't have a digit for 5 (five is represented by 10 in base 5). If you understand how to count, then this should be an aha moment at the absurdity of what was written.

 

I could expand on more problems with the riddle (I actually analyzed several others before seeing the fundamental counting problem), but I don't think it's valuable to delve deeper because the problem statement itself is clearly broken. I used spelling as a visual example, but this is really deeper than spelling. It's striking at the very fundamentals of math. I get on a bit of a soap box when it comes to math because these simple fundamentals are actually wrought with incredibly deep truths....and our educational system totally misses it - at all levels of education. I also have a huge vendetta against this "infotainment" crap that propagates social media. It's not that I'm against information being entertaining, but it should never be at the expense of truth. The laziness that goes into these little quips really erodes away at the knowledge of our culture - but it often goes by ignored because of the satisfaction we feel for "seeing it". I'm not just talking math riddles, but all the other reductionist simplification of incredibly complex interactions. My Facebook wall is full of "friends" posting these prideful, yet ignorant remedies.

 

Back to this riddle, you only "see it" when you don't submit to a proper understanding of counting and addition....and yes, it's really that bloody fundamental. The crazy thing is it wasn't until well after college that I realized I hadn't learned how to count properly. Not that I couldn't count, but I didn't fundamentally understand it to the level I do now....and it's that new understanding that makes this riddle incredibly annoying. I think we way underemphasize the wisdom of the ancients that were exploring the depths of mathematics. 

 

 

In other words, I agree with Quiet Hollow who said it in much fewer words