Recently i attended a cocktail party.there was a beautiful young woman,who also seemed very witty and intelligent.one of the other guests suddenly popped a question at her "how old r u?" for a moment she looked a bit embarrassed and while i stood there wondering how she was going to wriggle out of situation ,she flashed a charming smile and answered,"my age three years hence multiplied by 3 and from that subtracted three times my age three years ago will give you my exact age".
The man who had asked her the age just walked away puzzled.then she leaned over and whispered to me "if he can calculate that one,he deserves to know my age."
how old do u think she was?
ANSWER IS ...............
This problem can be solved only by application of algebra.supposing we take x for the years,the age three years hence will be x+3 and the age three years ago x-3
now we have the equation 3(x+3)-3(x-3)=x
when we solve this,we obtain;18.the girl is 18 years old
to check this:three years hence she will be 21 and three years ago she was 15
and the difference is (3*21)-(3*15)=63-45=18