Question

In 3 years from now the sum of juhi's age and jai's age will be 42 years. Juhi's age is also the difference between her own age and jai's age. How old is jai?
a)9 years
b)12years
c)18years
d)24years​

Answer 1

Answer:

Option (d) 24 years is correct.

• Age of Jai is 24 years.

Explanation:

Let, Present age of Juhi be x

and  Present age of Jai be y

Then,

As given Juhi's age is equal to the difference between her own age and Jai's age,

so,

→ x = y - x

→ 2 x = y  _____equation ①

Also, given that 3 years from now the sum of Juhi's age and Jai's age will be 42

so, 3 years later juhi's age = x + 3  and

3 years later Jai's age = y + 3

hence,

→ x + 3 + y + 3 = 42

→ x + y + 6 = 42

→ x + y = 36

Using equation  ①

→ x + 2 x = 36

→ 3 x = 36

→ x = 12  

Putting value of x in equation ①

→ 2 x = y

→ y = 2 ( 12 )

→ y = 24

Therefore,

• Present age of Jai is 24 years  &
• Present age of Juhi is 12 years.

Hence,

Option (d) 24 years is correct, Since Age of Jai is 24 years.

Answer 2

Let:

• Juhi's age be = x
• Jai's age be= y

then:

• 3 years from now, Juhi's age= x+ 3 years
• 3 years from now Jai's age= y+ 3 years

━━━━━━━━━━━━━━━

Given:

3 years from now the sum of juhi's age and jai's age will be 42 years.

thus we can say,

(x+3)+ (y+3)= 42 years

⟶ x+y+6=42 years

⟶ x+y= 42-6 years

⟶$\pink{\boxed{ x+y = 36 years----i}}$

━━━━━━━━━━━━━━━━

Also given:

Juhi's age is the difference between her own age and Jai's age.

thus:

x= y-x

⟶ x+x= y

⟶$\pink{\boxed{ 2x= y-----ii}}$

━━━━━━━━━━━━━━━━━━

Now by substituting y= 2x in equation 1 we get:

x+y= 36 years

⟶ x+ 2x= 36 years

⟶ 3x= 36 years

$\bold{\red{⟶x=12 years}}$

From equation 2 we know,

y= 2x years

⟶ y = 2× 12years

$\bold{\red{⟶y= 24 years}}$

━━━━━━━━━━━━━━━━━━

Thus, Juhi's age = 12 years and Jai's age is 24 years.

✔Option D is the correct answer.