The age of three daughters

[barry houdini]

Can someone explain the ballet relevance?

ballet itself isn't relevant, just that he refers to "the oldest" - the implication being that the ages must be 9, 2 and 2 rather than 6, 6 and 1 where there is no "oldest" (although I presume one of the 6 year olds must be older than the other, even if they are twins!)

 

[barry houdini]

What is the point of adding the sentence about the house number to the riddle, if it is not part of the solution?

It is part of the solution, because it tells you that the sum of the ages is a number that can be achieved more than one way (within the first constraint that the product should be 36). You don't need to know what the number is (although it can only be 13)

 

[Jonmo1]

It is part of the solution, because it tells you that the sum of the ages is a number that can be achieved more than one way (within the first constraint that the product should be 36). You don't need to know what the number is (although it can only be 13)

OK, I get that now thanks.

But I think the answer should be 6 6 1, not 9 2 2
Because of the senctence
The oldest dance ballet.
Either way you read 6 6 1 and 9 2 2, there is most likely a set of twins.
We must assume it is NOT a typo (untill otherwise corrected by the poster)
And the word dance is meant to be plural.
It seems gramatically correct to me, to refer to a set of twins as your oldest.
So the oldest is the set of 6 year old twins.

 

[barry houdini]

Now I re-read it I think you're right Jonmo!.......[as per drsarao's answer also]

 

[Norie]

Why 13?

 

[Jonmo1]

Why 13?

Because 13 is the only possible number that is the SUM of 3 numbers, where there are multiple possible 3 numbers whose product are 36.

Any number other than 13, would have been enough information to solve the riddle without knowing the oldest dance ballet.

 

[barry houdini]

There are 8 possible solutions for ages that multiply to 36 (I think). That's

1 1 36,
1 2 18,
1 3 12,
1 4 9,
2 2 9,
1 6 6,
2 3 6,
4 3 3

....and out of those only 2 add up to the same total (2 2 9 and 1 6 6 sum to 13) so if the mathematician still can't know what the ages are once he knows the house number then it must be 13 because that's the only number that wouldn't point to a specific solution

 

[Marcelo Branco]

Hello friends,

Very sorry about my bad english...

My intention was to say: The oldest dances ballet.

So 9,2 and 2 are the correct answers

M.

 

[drsarao]

Marc at last owns up! 2-2-9.
Quite a lot of traffic it generated.
I must shamelessly admit that I got the logic (though not the solution) from worldwideweb,
Cheers!
Marc, come up with another. It makes the forum interesting.
Moderator(s) may consider starting a separate Thread Group titled Quizzes. (Preferably, but not necessarily related to Excel).

 

[schielrn]

Marc at last owns up! 2-2-9.
Quite a lot of traffic it generated.
I must shamelessly admit that I got the logic (though not the solution) from worldwideweb,
Cheers!
Marc, come up with another. It makes the forum interesting.
Moderator(s) may consider starting a separate Thread Group titled Quizzes. (Preferably, but not necessarily related to Excel).

Here are a lot of brain teasers:

http://www.mrexcel.com/forum/showthread.php?436925-Brain-Teasers&highlight=riddle