Suppose that a 10-mbps wireless station is transmitting 50-byte frames one immediately after the other.
i) how many frames is it transmitting per second?
ii) if the probability of a frame being damaged (having at least one wrong bit) is 0.004, approximately how many frames will be damaged in one hour?

There are 1'000'000 Bytes in a Megabyte. In 10 Megabytes there are 10'000'000 bytes. So if it were transmitting 1-byte frames then the answer would be 10'000'000 frames. However this is not the case, because it is transmitting 50-byte frames, so we must divide 10'000'000 by 50.

Therefore, the answer to part (i) is: 200'000 Frames/second

If there are 200'000 Frames/second, then there are 12'000'000 Frames/hour (we get that by multiplying 200'000 by 60)

If the probability of a damaged frame is 0.004, then (multiplying 0.004 by 12'000'000) we get (ii) 48'000 Damaged Frames/hour