compounded interest issue

dusty6662002

I have been bothered by the interest problem a lot . How to canculate? Below is a typical example :

Mr. Daniel deposits $ 10,000 in a savings certificate earning p percent annual interest compounded quarterly. What is the  value of p?

(1) During the term of the certificate , he earns $18more than he would if the interest were not compounded .

(2) He withdraws all the money six months after depositing it . 

Please elaborate your answer and the way you get the analogy . Thanks in advance .