Question

Mary is twice older than her sister. In 5 years time, she will be 2 years older than her

sister. Find how old are they both now.​

Answer 1

AnswEr :

We're given with a condition that, Mary is twice older than her sister and in 5 years time, she will be 2 years older than her sister.

We've to find the age of Mary as well as her sister.

So,

Firstly let's form the equations according to the given conditions and then we'll simplify to get their age's.

Let's assume that,

• Age of Mary = x

• Age of her Sister = y

• 1st condition :

Mary is twice older than her sister.

• Present age of Mary = x = 2y

• 2nd condition :

In 5 years time, she will be 2 years older than her sister.

• Mary's age = 2y + 5

• Mary's sister's age = y + 5

Now, According to the given conditions,

Mary is twice older than her sister.

That is,

$: \implies \sf \: \: 2y+5 = (y+5 ) + 2 \\ \\ \\ : \implies \sf \: \:2y+5 = y+5+2 \\ \\ \\ : \implies \sf \: \:2y = y+7 -5 \\ \\ \\ : \implies \sf \: \:2y - y = 7-5 \\ \\ \\ : \implies \sf \: \:{ \underline{ \boxed{ \bf{ \red{ \: y=2 \: }}}}} \: \bigstar$

Hence, Age of Mary's sister is 2 years.

Age of Mary = 2y = 2 × 2 = 4 years.

Therefore, Mary's age is 4 years.

Answer 2

Given :-

• Mary is twice older than her sister
• After 5 years Mary will be 2 years older than her

To Find :-

• The present ages of both the sisters

Solution :-

First Of all we should create an equation and then we should satisfy their ages and we could find their present ages

• Let Marys age be x

• Let Mary's Sister's age be y

Case no :1

Marys age is twice than her sisters age

So, let us make an equation which satisfys the statement

• Present age of Mary = x = 2y

Case no:2

In a period of 5 years Mary will be 2 years Older than her sister.

• Mary's age = 2y+5

• Mary's Sister's age = y+5

Now,

According to the conditions given in the statement or Question above lets do the necessary calculations.

So, let us adopt an equation on the above conditions.

$\sf{ \bold{2y + 5 = (y + 5) + 2}{} }{} \\ \\ 2y + 5 = y + 5 + 2 \\ \\ 2y = y + 7 - 5 \\ 2y - y = 7 - 5 \\ \\ y = 2$

Hence, ★ Mary's age = 2*2 = 4

★Mary's Sister's age = 2

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