Question

Rahul's father is thrice as old as Rahul. After 12 years he will be just twice his son.Find their present ages

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Answer 1

Answer:

Step-by-step explanation:

ANSWER:-

Given:-

• Let the present age of son be x.

• So,  Present age of Father is 3x

After 5 years :-

• Son's age will be x+12
• Father's age will be 3x+12

According to Question:-

$\sf{ 2[x+12] = 3x+12}$

$\sf{2x +24 = 3x+12} \\\sf{ 2x - 3x = 12 - 24}\\\sf{ -x = -12}\\\sf{x = 12 \ years}$

So, son's age is 12 years.

Father's age will be

$\sf{3(x) = 3 \times 12 = 36 \ years}$

Things to Note:-

• Do not consider such questions directly in two different variables
• Always assume a single constant x
• This helps to make equations easily
• Always use Elimination/ Substitution/ Cross Multiplication method when you get a question of two variables.
• Assume 2 variables only when 2 or more cases are given. In this question, we do not require it.
• Always assume the opposite of what is given .
• FOR EXAMPLE:-
• Here , it was given that father will be as twice as his son. According to this I shall have doubled the Father's age.
• BUT NO, we shall double the son's age as son will be equal only when his value will be greater. Increasing father's value will give wrong answer( Answers like son's age will be 4 years or something like that).

Answer 2

Step-by-step explanation:

____________________

Question :-

• Rahul's father is thrice as old as Rahul. After 12 years he will be just twice his son.Find their present ages

____________________

Given :-

• Rahul's father is thrice as old as Rahul.
• After 12 years he will be just twice his son.

____________________

To find :-

• Find their present ages ?

____________________

Solution' :-

supposed the Rahul's present age be x years

then

• Father's present age = 3x years
• Rahul's age after 12 years =( X + 12)
• his father's age after 12 years =(3 X + 12)

(3x + 12) = 2 (x + 12)

3x + 12 = 2x + 24

3x - 2x = 24 - 12

x = 12

Hence :-

• Rahul's present age =12 years

• his father's present age = (3 × 12 )years=36 years.