Question

Form the pair of linear equations in the following problems , and find their solutions (if they exist) by the elimination method.
1)  five years ago ,Nuri was thrice as old as Sonu. 10 years later, Nuri will be twice as old as Sonu . How old are Nuri and Sonu ?

Answer 1

Let Nuri's and Sonu's ages be = n and s respectively.
Five years ago, (n - 5) = 3x(s - 5) ==> 3s - n = 10    -----------------(1)
After 10 years, (n + 10) = 2x(s + 10) ==> 2s - n = - 10 -------------(2)

Subtracting (2) from (1), s = 20
==>putting s = 20 in (1) n = 3s - 10 = 3x20 - 10 = 50
Hence Nuri = 50 yearrs and Sonu = 20 years