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Old man,
Do not try to scare people.
That age puzzle is quite simple:
every 100 years (a century) that phenomenon of altering positions would repeat.
Here is the list of years passed from 2015 and the ages:
RESULT REACHED
100 ,193 ,139
RESULT REACHED
167 ,260 ,206
RESULT REACHED
178 ,271 ,217
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@
As pointed out above had calculation error.
The only rule for those ages is to minus 54 from Yang's age to get Wong's age.
No matter the ages are of 3 digits, 4 digits.....
-old man
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Again:
Let A be the age, Y be the # of years after 2015, then the age's last two digints Z21: MOD of (A+Y,100), the last digit is Z1: MOD of (Z21,10), the digit
next to it in the left is Z2: Integer part of (Z21 divided by 10).
Homework: find Y when yang's Z2 equals wong's Z1 and yang's Z1 equals wong's Z2.
That is the 2 digits of the couple alter positions again.
Hint: use computer programming. take Y as natural number 1, 2, 3.....
stop when it happens.
Warning: It could run the computation forever, it seems. Then try to prove in the way of 'Theory of Numbers' that it is impossible.
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Old man,
Do not try to scare people.
That age puzzle is quite simple:
every 100 years (a century) that phenomenon of altering positions would repeat.
Here is the list of years passed from 2015 and the ages:
RESULT REACHED
100 ,193 ,139
RESULT REACHED
167 ,260 ,206
RESULT REACHED
178 ,271 ,217
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-old man himself