Question

question maths maths

Answer 1

Answer:

18yrs of sunita and 9 of her brother

Step-by-step explanation:

let sunita's brother age =x

sunita age =2x

6yrs later

sunita age =2x+6

her brother age = x+6

According to question

(2x+6)+(x+6)= 39

3x+12=39

x=9 yrs

so her brother age is 9 yrs

and sunita age is twice so 2×9=18yrs

Answer 2

Question:

Sunita is twice as old as her brother. In 6 years, the sum of their ages will be 39. What are their ages now?

Answer:

The present ages of Sunita and her brother are 18 years and 9 years respectively.

Step-by-step-explanation:

Let the present age of Sunita be y years.

We have given that,

Sunita's present age is twice of her brother's present age.

∴ Sunita's brother's present age is half of Sunita's present age.

⇒ Sunita's brother's present age $\displaystyle{\sf\:=\:\dfrac{y}{2}\:years}$

Now,

Age of Sunita after 6 years = ( y + 6 ) years

Age of her brother after 6 years $\displaystyle{\sf\:=\:\left(\:\dfrac{y}{2}\:+\:6\:\right)\:years}$

From the given condition,

Sum of ages of Sunita and her brother after six years will be 39.

$\displaystyle{\therefore\:\sf\:(\:y\:+\:6\:)\:+\:\left(\:\dfrac{y}{2}\:+\:6\:\right)\:=\:39}$

$\displaystyle{\implies\sf\:y\:+\:6\:+\:\dfrac{y}{2}\:+\:6\:=\:39}$

$\displaystyle{\implies\sf\:y\:+\:\dfrac{y}{2}\:+\:6\:+\:6\:=\:39}$

$\displaystyle{\implies\sf\:\dfrac{2y\:+\:y}{2}\:+\:12\:=\:39}$

$\displaystyle{\implies\sf\:\dfrac{3y}{2}\:=\:39\:-\:12}$

$\displaystyle{\implies\sf\:\dfrac{3y}{2}\:=\:27}$

$\displaystyle{\implies\sf\:3y\:=\:27\:\times\:2}$

$\displaystyle{\implies\sf\:3y\:=\:54}$

$\displaystyle{\implies\sf\:y\:=\:\cancel{\dfrac{54}{3}}}$

$\displaystyle{\implies\:\boxed{\red{\sf\:y\:=\:18\:}}}$

∴ Sunita's present age = 18 years

Now,

$\displaystyle{\sf\:Her\:brother's\:present\:age\:=\:\dfrac{y}{2}}$

$\displaystyle{\implies\sf\:Her\:brother's\:present\:age\:=\:\cancel{\dfrac{18}{2}}}$

∴ Sunita's brother's present age = 9 years

∴ The present ages of Sunita and her brother are 18 years and 9 years respectively.