Question

If twice the son’s age in years is added to the age of his father the sum is 90. If twice the father’s age in year is added to the age of the son, the sun in 120. Find their ages.

Answer 1

let take son's age be x and father's age be y
y+2x=90
2y+x=120
solve these two eqns
u will get son's age will be 20 yes
father's age will be 50yrs

Answer 2

let the present age of sun be x
let the present age of father be y

If twice the son’s age in years is added to the age of his father the sum is 90

                              2x + y = 90.............................(i)


If twice the father’s age in year is added to the age of the son, the sun in 120.

                         2x + 2y = 120...........................(ii)
                          x  +  y   =  60
                                  x  =  60 -y................................(iii)

substitute eq (iii) in (i)
  
 we get 2(60-y)+y=90
         120- 2y + y = 90
                      -y   = 90 - 120
                      -y   = -30
                        y = 30

x=60 -30
x=30