Man's Age Now: Find Out His Digit Sum Born Year

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SUMMARY

The man was born in 1991, and in 2011, he was 20 years old, which corresponds to the digit sum of his birth year (1 + 9 + 9 + 1). As of 2015, the man is 24 years old. This conclusion is derived from the straightforward calculation of his age based on the current year minus his birth year.

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Albert1
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A man found (at year 2011) his age at that time was all the digit sum of the year when he was born,
can you tell me ,how old is he now ?
 
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Albert said:
A man found (at year 2011) his age at that time was all the digit sum of the year when he was born,
can you tell me ,how old is he now ?
[sp]The man was born in the year 1991 so that in the year 2011 his age was 1 + 9 + 9 + 1 = 20 years ...[/sp]

Kind regards

$\chi$ $\sigma$
 
the sum of digits cannot be > 28 as 3 digit number < 2011 largest sum of digits (1999) is 28
so the year is 19ab or 20cd ( digit positions)

take 19ab.
now 10 a+ b + 1+ 9 + a + b = 111
or 11a + 2b = 111 so a is odd
a = 9 , b = 1 giving 1991
a = 7 or below give b > 9 not possible

take 20cd
so 10c + d + 2 + c + d = 11
11c + 2 d = 9
c = 0 and d = fraction
so no solution
so only solution 1991 and age = 20
 
I mean how old is he now ?(year 2015)
 
Albert said:
I mean how old is he now ?(year 2015)

24 years now
 

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