Question

A father is 30 years older than his son, however, he will be only thrice as old as the son after 5 years. What is the father's present age ?

(a) 40 yrs
(b) 30 yrs
(c) 50 yrs
(d) None of these

Answer 1

Answer:

Step-by-step explanation:

Given,

A father is 30 years older than his son however he will be only thrice as old as the son after 5 years.

To Find,

Present age of the father.

Solution,

Let the present age son be x years.

And the present age of father be y years.

Here, y = x + 30 .. (i)

After 5 years,

Son's age = (x + 5) years.

Father's age = (y + 5) years.

According to the question,

⇒ 3(x + 5) = (y + 5)

⇒ 3x + 15 = y + 5

⇒ 3x + 15 = x + 30 + 5

⇒ 3x + 15 = x + 35

⇒ 3x - x = 35 - 15

⇒ 2x = 20

⇒ x = 20/2

⇒ x = 10 years.

Here, the son's present age is 10 years.

Now, the present age of the father,

Putting x's value in eq (i), we get

⇒ y = x + 30

⇒ y = 10 + 30

⇒ y = 40 years.

Hence, the father's present age is 40 years.

Answer 2

Given :-

A father is 30 years older than his son, however, he will be only thrice as old as the son after 5 years.

To Find :-

Age of father

Solution :-

Let the age of son be a and father age be b

Now

Present age of father = b

b = a + 30(1)

Now

3(a + 5) = b + 5

3a + 15 = a + 30 + 5

3a + 15 = a + 35

3a - a = 35 - 15

2a = 20

a = 20/2

a = 10 years

Age of father = b

b = 10 + 30

b = 40 years

Option A is correct

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