My old friend Bruno the mathematician released last week at his birthday party the following trivia :
"Twice in my life my age was equal to the largest prime divisor of the then current year".
Bruno is not senile, there is no reason not to believe him. As far as I know he was born after WWII and still does not consider retirement.
How old is Bruno?
There's not enough information to uniquely determine Bruno's age, but we can narrow it down to three possibilities.
Bruno could have been born in 1953, 1961, or 1972.
If he was born in 1953, he'd have been 7 in 1960 and 31 in 1984 (and would be 64 today, just shy of retirement age)
If he was born in 1961, he'd have been 37 in 1998 and 53 in 2014 (and would now be 56)
If he was born in 1972, he'd have been 17 in 1989 and 29 in 2001 (and would now be 45)
In each case, his age in the listed year would be the largest prime divisor of that year.
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Posted by Paul
on 2017-08-23 11:41:27 |
solution
