MATH PUZZLE

40

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

Agree 40

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

the answer is not 40

96

90

96

1*4+1=5
2*5+2=12
3*6+3=21
8*11+8=96

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

96

88+8

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.

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.

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

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."

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 ?

96

so why isn't it 40?

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

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.

then, not the.

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

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

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.