Question

In 10 years, A will be twice as old as B was 10 years ago. If A is now 9 years older than B, than the present age of B is

Answer 1

Let Present Age of A= x yrs.
and of B= y yrs.

We are given,
                      (x+10)= 2(y-10) 
                       x+10= 2y-20
                       x-2y= -20-10
                       x-2y= -30.....................................(1)

                 and,x-y= 9.........................................(2)

                      By Subtracting Eqn. (2) from Eqn. (1)
                      +x-2y= -30
                      +x-y=     +9
                      -   +        -

                     ∴ -y=-30-9
                     so, y=39
                     By Putting y=39 in eqn. (2)
                     x-39=9
                     ∴x=48

         So, Present age of A = 48 yrs.
          and,Present age of B= 39 yrs.