Complexity of algorithms

How much time does an algorithm take to solve a problem of size n if this algorithm uses 2n^2 + 2^n bit operations, each requiring  10^-9  second, with these values of n?
i) 10
ii) 20
iii) 50
iv) 100

I need help with a question, the attachment contains the question as well as what I think is the answer.  Could someone please tell me if my answer looks right. If it is  not right  what steps should be taken to solve the problem.

thanks

Attached file(s):

Complexity of algorithms.doc  View File