Nigeria
1.find the back ground literature and give an economic explanation for
the development of the goverment budget and the balance of private
savings and investment of the country

2. Present the exchange rate system that this country adopts.how does
it work? what are the achievements of this system in this country?
what is the price the country has paid? will this system remain in the
future?

Thank you for your question.
 
I believe that to answer it well, your question will require more time
and effort than the average amount of time and effort associated with
this price. Here is a link to guidelines about pricing your question,
in the pricing guide: https://answers.google.com/answers/pricing.html

In addition, in your case, you've asked two questions. I suggest that
you'll divide them into two separate posts (and repost them as new
questions), thereby increasing your chances of getting an effective
answer.