UGC NET Paper 1 GA 2014 Dec Solved Paper

Let the present age of father is x and the present age of son is y.
As per question
$\left(3\mathit{x}-9\right)=2\times \left(5\mathit{x}-9\right)$
$\frac{\mathit{x}+\mathit{y}}{2}=27$
$\mathit{x}+\mathit{y}=54$ ...(1)
Again, $\mathit{x}+18=2\left(\mathit{y}+18\right)$
$\mathit{x}+18=2\mathit{y}+36$
$\mathit{x}-2\mathit{y}=18$ . ..(2)
On solving (1) and (2), we get.
$\mathit{x}=42$
$\mathit{y}=12$
Hence the present ages are 42 are 12.