The product of Tanvy's age (in years) 5 years ago and her age 8 years later is 30.

Let the present age of Meena be $x$ years.

According to the question:

$(x-5)(x+8)=30$

$\Rightarrow x^{2}+3 x-40=30$

$\Rightarrow x^{2}+3 x-70=0$

$\Rightarrow x^{2}+(10-7) x-70=0$

$\Rightarrow x^{2}+10 x-7 x-70=0$

$\Rightarrow x(x+10)-7(x+10)=0$

$\Rightarrow(x+10)(x-7)=0$

$\Rightarrow x+10=0$ or $x-7=0$

$\Rightarrow x=-10$ or $x=7$

$\Rightarrow x=7 \quad(\because$ Age cannot be negative $)$

Thus, the present age of Meena is 7 years.