The present age of father is 34 years more than that of his son. 12 years ago, father's age was 18 times the age of his son. The present age of son in years is :

Let us assume the present ages of son be Y then his father present age will be Y + 34 years. then
12 years ago, father's age = Y + 34 -12
12 years ago, Son's age = Y - 12
Now according to question,
12 years ago, father's age was 18 times the age of his son. then
18( Y - 12 ) = Y + 34 - 12
⇒ 18Y - 216 = Y + 22
⇒ 17Y = 238
∴ Y = 14
Hence, present age of his son = 14 years.