Form the pair of linear equations in the following problems,and find their solutions (if they exist) by the elimination method:
Five years ago,Nuri was thrice as old as Sonu. Ten years later,Nuri will be twice as old as Sonu. How old are Nuri and Sonu?

(N/A) Let the present age of Nuri be $x$ years and the present age of Sonu be $y$ years.
According to the given information:
Five years ago,Nuri's age was $(x-5)$ and Sonu's age was $(y-5)$.
$(x-5) = 3(y-5)$
$x - 5 = 3y - 15$
$x - 3y = -10$ $...(1)$
Ten years later,Nuri's age will be $(x+10)$ and Sonu's age will be $(y+10)$.
$(x+10) = 2(y+10)$
$x + 10 = 2y + 20$
$x - 2y = 10$ $...(2)$
Subtracting equation $(1)$ from equation $(2)$:
$(x - 2y) - (x - 3y) = 10 - (-10)$
$x - 2y - x + 3y = 10 + 10$
$y = 20$
Substituting $y = 20$ in equation $(1)$:
$x - 3(20) = -10$
$x - 60 = -10$
$x = 50$
Thus,the present age of Nuri is $50$ years and the present age of Sonu is $20$ years.