Question

I am F years old and my brother is B years older.What was the difference of our ages two year ago?

Answer 1

So the difference of ages 2 years ago is
`B` years.

Explanation:

The difference of age between me and my brother will not change whether we go back in time or forward in time, it will always be the same difference as of now. In this case it is B years. To further prove this we can do a calculation as below,

If I am F years old and brother is
`B` years older, the age of my brother is,

Age of the brother =
`F+B`

Age of me 2 years ago =
`F-2`

Age of my brother 2 years ago =
`F+B-2`

So the difference of ages 2 years ago can be calculated as,

Age of my brother 2 years ago - Age of me 2 years ago

=
`F+B-2` -
`F-2`

=
`F+B-2-(F-2)`

=
`F+B-2-F+2`

=
`B`