this is the question\

Assume that we have a link with bandwidth equal to 1 Mbps , where 1 bit takes 10 ms to reach the receiver (propagation speed is the same in both directions).

1. If we are utilization stop and wait ARQ for data link control, and assume the system data frames are 1000 bits in length, what is the utilization percentage of the link?

i did this part.. the answer is 10%

2. If we do not want to use stop and wait ARQ, and instead we have a protocol that can send up to 4 frames before stopping an waiting for an acknowledgement ?

i also did this.. the answe is 40%..the problem is in the next 2 questions:

3. what is the optimal number of frames (burst) that can be sent before stopping an waiting for an acknowledgement ?

4. What would be the actual throughput (Mbps) in the 3 previous examples if we assume that the acknowledgement will be lost once in each 2 bursts that we send (50 % unreliability) assuming that the retransmit will not be subject to corruption.
plz help