Question

the sum of fathers age and twice the age of his son is 70 if we double the age of the father and add it to the age of his son the sum is 95 find their present ages

Answer 1

Let the father's age be x and son's age be y.

x + 2y = 70   . . . . . (1)
2x + y = 95   . . . . . (2)

(2) * 2 => 4x + 2y = 190 . . . . . (3)

(1) - (3) 
-3x = -120
   x = 40
   y = 15
Father's present age = 40 yrs
Son's present age = 15 yrs

Answer 2

let the father's age be x and his son's age be y
ATQ-
x+2y = 70 --------(i) ×2
2x+y = 95 ---------(ii)
substracting equations (i) and (ii)
2x+4y = 140
- 2x+y = 95
__________
3y = 45
y = 15
putting value of y in equation (i)
x+2y = 70
x+2×15 = 70
x = 70-30
x = 40
father's age = 40
son's age = 15