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Topic: Faites vos jeux messieurs, dames (Read 3 times) previous topic - next topic

robtillaart

A hint ...

The product of the ages = 36, that means the list of possible combinations is:

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

(2) The sum of their ages is the number of cars in my street.
(3) And to determine their ages you must know that the youngest was ill recently.

3) states that even when you know the number of cars in my street, you still need extra information

...



Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

radman

There has to be 'a' youngest so that seems to pin it down to;
Code: [Select]

1 2 18 sum 21
1 3 12 sum 16
1 4 9  sum 14
1 6 6  sum 13
2 3 6  sum 11


But I don see how "The sum of their ages is the number of cars in my street" comes into play.

robtillaart

OK,

(1) The product of the ages = 36
(2) The sum of their ages is the number of cars in my street.
(3)  And to determine their ages

Given the fact that I know the # cars in my street and I still say the first half of sentence 3, implicates that from the product and sum alone one cannot determine the ages.

1 1 36 sum 38
1 2 18 sum 21
1 3 12 sum 16
1 4 9 sum 14
1 6 6 sum 13
2 2 9 sum 13
2 3 6 sum 11
3 3 4 sum 10

given that sum and product is not enough to determine leaves only 2 options.

1 6 6 sum 13
2 2 9 sum 13

and the youngest was recently ill,  so ....


Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

radman

Ah the light comes on - very clever.

robtillaart

I recall it took me quite some time too.
The trick is that you must not think from what you know , but from what the other person knows.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

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