### Brain Teasers

# Half of Five

If half of 5 is 3; then how much is

one-third of 10?

one-third of 10?

### Answer

Answer: 4If half of five is 3, then 5 is not actually

five; it represents 6. If 5 represents six,

then 10 would in fact represent 12.

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## Comments

I don't like the explaination in the answer.

My answer was 3: the answers are rounded to the nearest

integer, with the usual convention that .5 gets rounded up.

Or it could be 4, if the answers are simply rounded up.

But I don't follow the reasoning that "if 5 is really 6, then 10 must be 12."

If 5 isn't really 5, then why should we assume that one third is the

same as division by three?

My answer was 3: the answers are rounded to the nearest

integer, with the usual convention that .5 gets rounded up.

Or it could be 4, if the answers are simply rounded up.

But I don't follow the reasoning that "if 5 is really 6, then 10 must be 12."

If 5 isn't really 5, then why should we assume that one third is the

same as division by three?

And John Lennon is the Walrus. These puzzles that make you suspend regular rules are more difficult as you can't really figure any reliable pattern, like you said about 1/3 really being division by 3. If half of 5 equals 3, then 3 is really 2.5 and then 1/3 of 10 is really 1/2.5 of 10, being 4, so go figure.

There's a rule in reasoning: -----

If the antecedent is false, the reasoning is true regardless of the consequent.

So: "If half of 5 is 3; then

one-third of 10 is 37054872" or "If half of 5 is 3; then one-third of 10 is 0" are both true.

This teaser belongs in the Logic section, or perhaps in a new Illogic section.

If the antecedent is false, the reasoning is true regardless of the consequent.

So: "If half of 5 is 3; then

one-third of 10 is 37054872" or "If half of 5 is 3; then one-third of 10 is 0" are both true.

This teaser belongs in the Logic section, or perhaps in a new Illogic section.

May 11, 2005

I'd love to see that section!!

Or if you "round up", then 10 / 3 = 3.333, rounded up is 4.

this is pretty lame. since when is 5=6?

i just guessed and i got it right

i second the illogic category idea

That was a complicated way to say you round up to the nearest whole number.

The number '5' is just being used as a variable to represent 6, and '10' is a variable that represents a number twice its size. So it is saying, "if x / 2 = 3, then 2x / 3 = ?" I understand the reasoning, but I only got it right because I thought the numbers were simply being rounded up.

wth?

The answer says that "half of 5 is 3" implies that "5" is a variable to represent "6". But it could equally imply that "half of" is a variable meaning "one million times" or that "3" is a variable meaning "pi"...

The answer could be anything. :?

The answer could be anything. :?

Everyone else is right.

This could be translated like this:

If-The

Half of-answer

5-to this

is-is

3,-french

then-fries

one-third of 10-.

is-.

what?-.

This could be translated like this:

If-The

Half of-answer

5-to this

is-is

3,-french

then-fries

one-third of 10-.

is-.

what?-.

I had the same answer as dewtell: three or four. Assuming you are taking half of something that can't be divided (such as half the children), then the meaning of half is "half rounded" or "half truncated".

This answer doesn't require the creation of new rules of math and number values, and I think has to be considered the correct answer. Otherwise I could say that the answer is 47 because five is really 22 and three is really 11 and 10 is really six and 47 is really three.

Who approves these?

This answer doesn't require the creation of new rules of math and number values, and I think has to be considered the correct answer. Otherwise I could say that the answer is 47 because five is really 22 and three is really 11 and 10 is really six and 47 is really three.

Who approves these?

I meant "47 is really two" above...I got confused about what my imaginary number system was.

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