Question

The age of a person is thrice the total ages of his 2 daughters. 0.5 decades hence, his age will be twice of the total ages of his daughters. Then what is the father’s current age? [0.5 Decades = 5 Years]

A) 35 years B) 40 years C) 45 years D) 47 years

Answer 1

Given that:

• Age of a person is thrice the total ages of his 2 daughters.

• 5 years hence, his age will be twice of the total ages of his daughters

To find :

• Present age of father.

SoluTion:

Let the age of daughters be x years and age of father be y years.

According to the question,

• 3x = y.......(1)

5 years hence,

• Age of daughters = x + 10 ( 5 for each daughter )
• Age of father = y + 5

$\implies$ 2(x + 10) = y + 5

$\implies$ 2x + 20 = y + 5

$\implies$ 2x - y = 5 - 20

$\implies$ 2x - y = -15

From (1),

$\implies$ 2x - (3x) = -15

$\implies$ 2x - 3x = -15

$\implies$ -x = -15

$\implies$ x = 15

Hence, age of daughters be 15 years.

$\rule{200}2$

Now, put the value of x in eq (1),

$\implies$ 3 × 15

$\implies$ 45

Hence, age of father be 45 years.

$\therefore$ Option C) is correct.

Answer 2

SoluTion:

• Let age of daughter be x years

• Let age of father be y years.

•°• 3x = y........(1)

Also, after five years,

Age of daughter = x + 5

Age of father = y + 5

So, according to the question,

$\longrightarrow$ 2(x + 10) = y + 5

$\longrightarrow$ 2x + 20 = y + 5

$\longrightarrow$ 2x - 3x = 5 - 20

$\longrightarrow$ -x = -15

$\longrightarrow$ x = 15

Thus, age of daughter will be 15 years.

Put x = 15 in (1)

$\longrightarrow$ 3(15) = y

$\longrightarrow$ y = 45

Therefore, option C) 45 years is correct.