Correct Answer - Option 2 : 7 : 3
Ten years ago, let the age of mother and her son be 3x and x respectively
According to the question
(3x + 20)/(x + 20) = 2/1
⇒ 3x + 20 = 2x + 40
⇒ x = 20
Present age of mother = 3 × 20 + 10 = 70 years
Present age of her son = 1 × 20 + 10 = 30 years
∴ Present age ratio of mother to her son = 70 : 30 = 7 : 3