Question

Luara is 5 years older than his sister Elisabeth. She figured out that in 4 years she will be two times older than Elisabeth. How old are they now?

Answer 1

Elizabeth age = 1 year and Laura age= 6 years

Explanation:

Let x be the age of Elisabeth then according to the question we have

Age of Laura= x + 5

After 4 years,

Elizabeth's age = x + 4

Laura's age =x + (5+4) = x + 9

Looking into the question again we have

x + 9 = 2 (x + 4)

x + 9 = 2x + 8

2x - x = 9 - 8

x = 1 which is Elisabeth age

And age of Laura is x + 5 so 1 + 5 = 6

Answer 2

Laura's age is
`6` years old

Elisabeth's age is
`1` year old

Explanation:

Let

x-----> Laura's age

y----> Elisabeth's age

we know that

`x=y+5` -----> equation A

`x+4=2(y+4)` -----> equation B

substitute equation A in equation B and solve for y

`y+5+4=2(y+4)`

`y+9=2y+8`

`2y-y=9-8`

`y=1\ year`

find x

`x=y+5`----->
`x=1+5=6\ years`