What's your first answer to this problem?

[viper37]

Surely the plus sign should be replaced with another symbol.

A+B=C is A*B+A=C.

[Grinning_Colossus]

Other, 52

[Admiral Yi]

A+B=C is A*B+A=C.

That's my point.  "+" already has a narrowly defined meaning.

[CountDeMoney]

even when I looked at the spoiler couldn't see where the 40 came from 

[spoiler]He's keeping a running tally of the totals of all the numbers on the left side of the four "equations"[/spoiler]

Well that's pretty silly.

[Valmy]

even when I looked at the spoiler couldn't see where the 40 came from 

[spoiler]He's keeping a running tally of the totals of all the numbers on the left side of the four "equations"[/spoiler]

Well that's pretty silly.

Why? When you look at the totals always going up that is the obvious solution

[CountDeMoney]

Why? When you look at the totals always going up that is the obvious solution

There are 4 equations listed.
The first one listed is correct.
The next two equations are incorrect--those are problems, but the problem "why can't Marti do basic addition?" Is not the problem that is asked to be solved.
The last equation--the one with the "?"--is the only problem to solve.

Therefore, the answer to 8 + 11 = ? is 19, as ? = 19.

Talk about an obvious solution. 

[Eddie Teach]

That is one way of looking at it. However, if we assume Marty is asking us to solve for the system and not just the equation, those two faulty equations need to be dealt with.

[The Brain]

CdM fights the system.

[dps]

Agree with Seedy on this.  The way Marti presents it, all 4 equations are independent;  there is nothing to indicate that the answer to the 4th equation is dependent any information contained in the other 3.  There are ways to state it such that each equation is dependent on those which precede it, but Marti didn't do so.

[CountDeMoney]

Well, when I see a question mark at the end of a basic addition problem, I answer the question mark.  That's MY policy. [/frankdrebin]

[Razgovory]

Seedy is smarter then you all

[Monoriu]

Answer A.  Couldn't figure out how to get answer B on my own.

[crazy canuck]

The problem:

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

A: [spoiler]96[/spoiler]
B: [spoiler]40[/spoiler]

I am curious because both answers work but I guess which one you go to first tells something about how you think.

A

[DGuller]

Answer B.  Wouldn't even think of the first approach until I saw the number, and then realized what I had to do given its magnitude.

[Admiral Yi]

What would be the proper way to notate the question?

I was thinking f(1,4)=5, etc, but that would rule out the sequence, wouldn't it?