SOLUTION: our mother is 3 times as old as my brother and i am 1/3rd times older than my brother. if 4 years ago i was as old as my brother today, what is the age of my mother?

M = 3B

You lost me there.  Are you 1/3 as old as your brother?
If so you are YOUNGER, not OLDER, than your brother.
Or are you your brother's age plus 1/3 of his age older?

If the first way, the equation is

I = B

If the second way then the equation is

I = B + B

I - 4 = B

I'll try it both ways, but now I believe you meant the
second way.  Otherwise this last sentence wouldn't make
sense.

First way



I will assume you know how to solve a system of
equations.  If you don't post again asking how
to solve this system.

No that give B=-6, I = -2 and M = -18.

Second way:

Since ages can't be negative, you must have meant the 
other way:

 

Simplify the second equation:



Multiply through by 3







Solve that system and get B = 12, I = 16 and M = 36

So you are 16, your brother is 12, and your Mother is 36.

Edwin