John was born in 19ab. The two digit number ab when divided by 2 gives his age on his birthday in 1999.
Can you tell me how old was he?
Hello, getmath!
Another approach . . .
John was born in $\displaystyle 19ab$.
The two-digit number $\displaystyle ab$ when divided by 2 gives his age on his birthday in 1999.
Can you tell me how old was he?
Let $\displaystyle x\,=\,ab$
He was born in the year $\displaystyle 1900 + x$
$\displaystyle \frac{x}{2}$ years later, it is 1999.
Hence: .$\displaystyle (1900 + x) + \frac{x}{2} \:=\:1999\quad\Rightarrow\quad x\:=\:66$
Therefore, he was born in $\displaystyle 1966$; he was $\displaystyle 33$ in 1999.