So for the first part, I simply figured as its a single packet, the new length would be F+H.
and since the speed between all links is R KB/S - then from start to the first router would be F+H/R.
Then I multiply this by number of links which is N - therefore a) is ((F+H)/R)*N
However for part b)
I tried splitting it up like so:
((F/P)+H) - new length of each segment,
((F/P)+H)/R - time taken for one segment to go from A to first router.
N*((F/P)+H)/R - time taken for one segment to reach B.
P*(N*((F/P)+H)/R - time taken for all segments to reach B.
This is somehow wrong and the correct answer is:
(N+P-1)*((F/P)+H)/R
Could someone help me out here.