Question

Please help.

2 years ago, age of brother was 3 times less than sister's age. this year his age is just 2 times less than his sister's. how old is brother? how old is sister?​

Answer 1

The sister's present age is 8 years old, and the brother's present age is 4 years old.

Explanation:

Let
`b =` present age of the brother,
`s =` present age of the sister

`s-2 = (b-2)` ×
`3`

`s-2` =
`3b - 6`

`s = 3b - 4`

`s = b` ×
`2`

`= 2b`

`sb-4 = 2b` (proved from above equations)

`b = 4`

`\because s = 3b - 4`

`\therefore`
`s = 3`×
`4 - 4`

`= 8`

`\therefore` the brother's present age is 4 years old, and the sister's present age is 8 years old.

Hope this helps :)

Answer 2

`The\ brother's\ present\ age= 4\ years\\The\ sister's\ present\ age=8\ years`

Explanation:

`Let\ the\ brother's\ present\ age\ be\ x\\Hence\ we\ are\ given,\\His\ sister's\ present\ age=(2x)\\Now,\\The\ brother's\ age\ before\ two\ years=(x-2)\\The\ sister's\ age\ before\ two\ years=3(x-2)\\Also,\\His\ sisters\ age\ before\ two\ years=2x-2\\Hence,\\3(x-2)=2x-2\\3x-6=2x-2\\3x-2x=6-2\\x=4\\Hence,\\The\ brother's\ present\ age= 4\ years\\The\ sister's\ present\ age=2x=2*4=8\ years`