## How Old, Again?Math brain teasers require computations to solve.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?
## AnswerAs 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. Hide ## What Next?
Tweet
See another brain teaser just like this one...Or, just get a random brain teaser If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own. Back to Top |