Friday Puzzler -- Symbol Arithmetic

Re: Friday Puzzler -- Symbol Arithmetic

JohnV

Legal alcohol age - II

Let the answers flow!

Alex Y

I'm not going to say yes or no to any answers initially -- let's see what folks come up with. If no consensus develops, we might need to ask for rationale for some answers.

Legal drinking age

Alex Y

John, depending on jurisdiction, I interpret your answer to be 10 or 7. Which is it, or did I misunderstand your answer?

Re: Legal drinking age

JohnV

Misunderstood. I also can count in Roman numerals.

Re: Legal drinking age

Alex Y

Aha! 16 or 19?

Re: Friday Puzzler -- Symbol Arithmetic

Ed in Leaside

1543165

oops 154388

Re: Legal drinking age

JohnV

reasoning First three rows. 15 sides in each geometric symbol. 4 bananas in each bunch and the hour hand points to three.

Last row each number value of each symbol is different than in the first three rows.

Re: Friday Puzzler -- Symbol Arithmetic

Sam Force

67

Re: Friday Puzzler -- Symbol Arithmetic

Larry Barrett

38

Re: Friday Puzzler -- Symbol Arithmetic

Henry Higginbotham

Looks like 88 to me, too.

Re: Friday Puzzler -- Symbol Arithmetic

Ed in Leaside

Larry has it. I knew I was wrong a couple of minutes after posting ...

(2+3+3)x11=88

2+3+3x11=38

Well, duh

Henry Higginbotham

Order of Operations, and all that. I'll just go back to my nap now.

Re: Friday Puzzler -- Symbol Arithmetic

john in lutz

2+4+4x15=150

Re: Legal drinking age

JohnV

must be getting blind. totally missed the multiply in last row. 88 it is.

Answer

Alex Y

Well, we don't have consensus, but a clear plurality now support the correct answer first given by Larry, of 38.

This had two catches, which can lead to lots of wrong answers.

The first was caught by JohnV, who pointed out that while it was tempting to evaluate the symbols as

Nested polygons = 15,

Bunch of bananas = 4, and

Clock = 3, in fact there were

15 edges in the nested polygons in the first three lines, but only 11 in the last line, and

4 bananas in first bunches versus 3 in last line, and

Clock showing 3 o'clock initially, and 2 o'clock in last line

Ed, Henry, and JohnV used this info to apply the operations left to right to come up with 88.

But that brings up the second "trick", and that is the order of operations, which caused Ed and Henry to change their vote. In a string like this, multiplication and division is performed before addition and subtraction. So 2+3+3x11 is evaluated as

2+3+(3x11), not (2+3+3)x11