A father tells his son,"I was of your present age when you were born." If the…

To find the age of the boy 5 years ago, we can use algebraic expressions to represent the relationship between the father's and the son's ages.

Step-by-Step Analysis
Define Variables:

Let the son's current age be x.

When the son was born, the son's age was 0.

At that time, the father was x years old (based on the statement "I was of your present age when you were born").

Formulate the Father's Current Age:

Since the father was x years old when the son was born, the father is currently x + x = 2x years old.

We are given that the father is currently 36 years old.

So, 2x = 36.

Solve for x (Son's current age):

x = 36 / 2 = 18 years old.

Calculate the Son's age 5 years ago:

Son's age 5 years ago = 18 - 5 = 13.