How do I calculate the response time of a multiple core processor given certain information? [on hold]

On my homework the question asks:

A program executes serially in 200 seconds. If it is parallelized, 7 seconds of overhead are required for synchronization, locking, and communication. Compute the execution time, ideal speedup (if there were no overhead required), actual speedup, and the percentage of the ideal speedup that is obtained for 1, 2, 4, 8, 16, 32, 64, and 128 processors.

How do I calculate the answer to this? It is not something that has been covered in class yet and the homework is due before the next time the class meets.

My guess is that I divide 200 seconds by the number of cores and then add 7 * # cores to get the total response time.

I know how to calculate speed up percentage so that is no big deal.

Thanks for looking, Zach