Radha get married 6 years ago. Today her age is 1 1/ 4 times her age at the time of marriage. Her son's age is 1/10 times her age. Her son's age is :

Let us assume the present age of Radha be Y years; then
Before 6 years Radha's age will be Y - 6 years.
According to question,
Today her age is 1¹/₄ times her age at the time of marriage,
5/4 ( Y - 6 ) = Y ( Since 1¹/₄ = 5/4 )
⇒ 5Y - 30 = 4Y
∴ Y = 30 years
Hence, her son's age = 30 x 1/10 =3 years