Any number \(x\) is called irrational if it cannot be expressed in the form of \(\frac{p}{q}\) where \(p\) and \(q\) are integer and \(q\neq 0\) otherwise it is said to be a rational number.
 
Based on the above information answer the below questions.
 
1. \(\sqrt{8}+2\) is
 
2. Which of the following is not an irrational number ?
 
3. \(\sqrt{20}-\sqrt{15}\) is 
 
4. Which of the following is not a rational number ?