Question

A man is 6 times as old as his son. Twenty years later, the man will be twice as old as his son. Find the age of the man when his son was born. Solve the problem using algebra.

a) 12 years old
b) 15 years old
c) 18 years old
d) 21 years old

Answer 1

The age of the man when his son was born is 30 years.

Step-by-step explanation:

Let's assume the age of the son is x years. According to the given information, the man is 6 times as old as his son, so the age of the man would be 6x years.

Twenty years later, the man will be twice as old as his son. So we can write the equation:

6x + 20 = 2(x + 20)

Solving this equation, we get:

6x + 20 = 2x + 40

4x = 20

x = 5

Therefore, the age of the man when his son was born is 6x - x = 30 years.