Question

The son's age is one-third that of his father. Five years ago father's age was 4 times as old as his son. Find their present age.



....and also please give me the final answer.​

Answer 1

Answer:

let the present age of son be x

son's age is one - third of his father's age =

y=x ---- (1)

3

5yrs ago father's age was 4 times of his sons age

y= 4x-5 ---(2)

Step-by-step explanation:

this is the equation we get

Answer 2

Given:

• Son's age is ⅓ that of his father.
• Five years ago, father's age was 4 times his son's age.

To Find:

• What are their present ages?

Process:

To find their present ages we will first let the father's age be x. Then, son's age will be x/3. Five years ago son's age will be (x/3 - 5) and father's age will be (x - 5). It is given father's age was 4 times son's age. So, we can form an equation as follows:

• x - 5 = 4(x/3 - 5)

After solving the equation to get the value of x, the value of x is equal to the age of the father and x/3 will be the age of the son.

Solution:

Let the father's age be x.

Then, the son's age will be x/3.

Five years ago:

Son's age = (x/3 - 5)

Father's age = (x - 5)

∵ Five years ago father's age was 4 times his son's age. [given]

$\therefore\sf{x-5=4\bigg(\dfrac{x}{3}-5\bigg)}$

$\implies\sf{x-5=\dfrac{4x}{3}-20}$

$\implies\sf{x-\dfrac{4x}{3} = 5-20}$

$\implies\sf{\dfrac{3x-4x}{3}=-15}$

$\implies\sf{\dfrac{-x}{3}=-15}$

$\implies\sf{-x=-15\times3}$

$\implies\sf{\not\!\!{-}x=\not\!\!{-}45}$

$\implies\sf{x = 45}$

Hence, value of x is 45.

Therefore, father's age = x = 45 years

And son's age = x/3 = 45/3 = 15 years