This is a computer networks problem, thanks for your help!

Consider a simple network that is composed of two computers (A & B) and a router X in the middle. Com- puter A is connected to X by a link that is 1 Mbps and has a propagation delay of 1 msec. Computer B is connected to X by a link that is 2 Mbps and has a propagation delay of 2 msec. Suppose that computer A generates two packets (destined to B) that are sent back-to-back via router X. Assume that each packet is 1000 Bytes in size. Answer the following questions [2 pts each: (a) When would the first packet arrive fully at X? (b) When would the first packet arrive fully at B? (c) When would the second packet arrive fully at B? (d) Would this "packet-pair" still arrive back-to-back at B? If your answer is yes, indicate why. If your answer is no, indicate the time gap between them (the time between when the last bit of the first packet was received and when the first bit of the second packet was received)