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MATH PUZZLE

rattdog
rattdog95232

New York

3 yrs ago · 1 min read

i know there are some math enthusiasts on this board. just found this puzzle on youtube moments ago. supposedly only in 1000 can solve it correctly, which for some reason blows my mind away. the puzzle goes:

1=4=5 2+5=12 3+6=21 8+11=?

Replies (19)Latest

Profile picture for misterorange
misterorange

40

I'm assuming the first line should read 1+4=5

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wld4tatas

Agree 40

Profile picture for rattdog
rattdog

correction: 1+4=5 for the first line.

the answer is not 40

Profile picture for mark94
mark94

96

Profile picture for twentyfive
twentyfive

90

Profile picture for Dolfan
Dolfan

96

14+1=5 25+2=12 36+3=21 811+8=96

Profile picture for twentyfive
twentyfive

^ sorry my 90 was a typo I concur with both of the above 96

Profile picture for founder
founder

96

88+8

Profile picture for rattdog
rattdog

congrats to all that replied correctly at 96.

and many thanks to dolfan for showing "all work" and the right efficient mathematic way to solving the puzzle.

i did it the hard way via running pattern.

Profile picture for From978
From978

Lots of math problems have more than one solution. (X squared equals 4 has two, for example.). The first one I thought of was A(B+1), which gives 96, but that certainly doesn't prove that 40 is wrong. If you can explain how you got some other answer, it also is a solution.

Profile picture for misterorange
misterorange

^^ OK I'll do it when I'm sober.

Profile picture for TallmanFL
TallmanFL

96, assuming the first line really is supposed to be 1+4=5.

The trick is that your "+" symbol means "take the first number, and multiply it by one more than the second number."

Profile picture for wld4tatas
wld4tatas

There is a logic to the answer of 40 but it's flawed, I did it too quick.

I agree 96 is the superior answer. Congrats to mark for getting it first.

Can we have another puzzle ?

Profile picture for FTS
FTS

96

Profile picture for Jascoi
Jascoi

so why isn't it 40?

is this why I have spent much more than I should have?

Profile picture for datinman
datinman

There is math and the there is pattern recognition.

Math: 8 + 11 = 19; regardless of the incorrect lines prior.

Pattern recognition: There are 2.

A) The sum above added to the addends below. You get 40.

B) 8*11+8=96. or The sum above added to the addends below accounting for the missing sequences. You get 96.

Three answers, all equally correct.

Profile picture for datinman
datinman

then, not the.

Profile picture for misterorange
misterorange

Okay, I agree that whether you get 40 or 96 they are both correct as the puzzle is presented.

The first one (40) is solved by adding the solution from the previous line. Ex: 3+6 doesn't equal 21 until you add the 12 from the line above. So the equations are interconnected both numerically and by following the same pattern. 1+4=5 2+5+5=12 3+6+12=21 8+11+21=40

In the other one (96) you are following the pattern of first multiplying by the same number which is to be added. Each line follows the same pattern, but numerically each line stands alone. The answer to one line is not dependent on the numbers from another line. 14+1=5 25+2=12 36+3=21 811+8=96

HOWEVER: Let's take another look at the original puzzle. This is interesting.

1+4=5 2+5=12 3+6=21 8+11=?

Read vertically, the first and second digits to be added. They begin 1,2,3 and 4,5,6. The pattern is disrupted with the fourth equation which skips from 3 to 8 and 6 to 11. Here's the part I find interesting. If you continue the pattern without disrupting the consistency, check out the solutions:

1+4=5 2+5+5=12 3+6+12=21 4+7+21=32 5+8+32=45 6+9+45=60 7+10+60=77 8+11+77=96

14+1=5 25+2=12 36+3=21 47+4=32 58+5=45 69+6=60 710+7=77 811+8=96

Profile picture for ancientlurker
ancientlurker

There is no puzzle, there are simply false statements. 2+5=12 is simply false, everywhere, always. Yes, I understand the "solution", I'm saying it's bullshit to write false statements. If there is an unknown in the equation, show a placeholder for it.

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