Question

10 years ago, mother was thrice as old as her daughter. Find the current age of daughter if, at present, mother is twice as old as her daughter.​

Answer 1

Answer:

The current age of the daughter is 20 years

Step-by-step explanation:

Let the current age of mother is x years and that of daughter is y years

10 years ago, the age of mother = x - 10

10 years ago, the age of daughter = y - 10

According to the question

x - 10 = 3( y - 10)

or, x - 10 = 3y - 30

or, x - 3y = -20        .............. (1)

Also at present the mother is twice as old as daughter

Thus,

x = 2y

Putting this value of x in eq (1)

2y - 3y = -20

or, y = 20

Therefore, x = 2 × 20 = 40

Therefore, the current age of mother is 40 years and the daughter is 20 years

Answer 2

Answer:

The current age of the daughter is $20$ and her mother age is $40$.

Step-by-step explanation:

Suppose the age of the daughter is $x$ year and the age of the mother is $y$ year.

$10$ year ago:

Daughter age was $= x-10$

And mother age was $= y-10$

And also mother was thrice older as her daughter $= 3(y-10)$

Hence according the question equation will be:

$x-10 = 3(y-10)$

$x-10 = 3y-30\\x = 3y-30+10\\x = 3y-20 --------eqn(1)$

Current Age:

Let the current age of the daughter is x

And her mother is twice as old as her daughter is 2y.

So according to the question equation will be:

$x = 2y$

Substituting the value of eqn(1) in the above equation we get:

$3y-20 = 2y\\3y-2y = 20\\y=  20$

Hence the current age of the daughter is 20 and her mother age is $(2\times 20)$ or $40$.