#11 - Mathematical Puzzle
Suppose I am a grandfather. My grandson is about as old in days as my son is in weeks. He is also as many months old as I am in years. Together, the three of us are 140 years old. How old am I?
As noted, all three are 140 years old. Thus, a+b+c=140, where a is grandfather, b is son, and c is grandson. Additionally, grandson being about as many days old as son is in weeks gives 365c=52b. Finally, the grandson being as many months as I am in years gives 12c=a. Thus, the following are known.
a+b+c=140
365c=52b or b=365c/52
12c=a
By calculation and substitution we have as follows.
12c + 365c/52 +c = 140
624c + 365c + 52c = 7280
1041c = 7280
c = 6.99, or 7 (teaser said 'about')
so, as 12c = a, then a = 84.
I am 84 years old.
As an aside, my son is 49
