A worker spends two-thirds of his salary for board, half
of the remainder for clothing and saves $2000 per year. How much is
his salary?
no matter how i explain my bro doesn't understand 
If the main problem is that your younger bro is unable to take
it in, then draw it out for him to see using model diagrams.
You will have to draw six boxes, show him that four boxes ( 2/3
) was spent for board, one box ( half of remainder ) was spent on
clothing, and the last box ( amount left ) is the $2000 that was
saved up.
Next, ask him to calculate the total amount of boxes, and ask
him to multiply that by the value of one box, so as to find the
salary of the worker.