This is a sample of some questions which have turned out to be difficult to me. I need help!

1. Can we say that the public key in Merkle-Hellman Cryptosystem is used to decrypt messages but cannot be used to encrypt messages. Is it true that the private key on the other hand is used to encrypt messages?

2. Determine another name that is used to refer to Merkle-Hellman Cryptosystem.

3. Describe the most secure public key distribution system.

4. Give examples of the systems that use timestamps.

5. Given a palindrome number, can a DFA be used to recognize it?

6. Describe the condition necessary for two finite states to be equivalent.

7. Determine the area of 11|z| 19.

8. Solve for 1/(a+1)+1/(b+1)+1/(c+1) where 1/(a+)+1/(b+)+1/(c+) equals 22 and 1/(a+2)+1/(b+2)+1/(c+2)equals 2 and the non-real cube roots are & 2.

9. Determine the value of E(x) given that P(x) = 0.5 and x = 4.

10. Determine the expected value of X a continuous random variable.