The product of Ramu's age (in years) five years ago

Solution:

Let the present age of Ramu be $x$ years

Then, 9 years later, age of her $=(x+9)$ years

Five years ago, her age $=(x-5)$ years

Then according to question,

$(x-5)(x+9)=15$

$x^{2}+9 x-5 x-45=15$

$x^{2}+4 x-45-15=0$

$x^{2}+4 x-60=0$

$x^{2}+4 x-60=0$

$x^{2}-6 x+10 x-60=0$

$x(x-6)+10(x-6)=0$

$(x-6)(x+10)=0$

So, either 

$(x-6)=0$

$x=6$

Or

$(x+10)=0$

$x=-10$

But the age never be negative

 

Hence, the present age of Ramu be $=6$ years