The HTML base file contains 10 embedded objects.
X: No. of Round trip time(RTT’s) that are required to retrieve the base file when the objects under non persistent HTTP with no parallel connection
Y: No. of Round trip time(RTT’s) that are required to retrieve the base file when the objects under non persistent HTTP with 6 parallel connections
Initially, we need 1 RTT for TCP connection establishment and 1 RTT to get the HTML base file i.e. 2 RTTs are needed for both the cases.
Retrieving 10 objects without parallel connection requires 20 RTTs. ( 1 RTT for TCP connection and 1 RTT for object retrieval i.e. 2 RTTs per object). Therefore, X = 2 + 20 = 22.
Retrieving 10 objects with 6 parallel connection requires 1 (TCP connection) + 1 (6 parallel connections for retrieval of 6 objects) + 4 (4 TCP connections) + 4 (Retrieval of 4 objects that are left) = 10 RTTs. Therefore, Y = 2 + 10 = 12.
So, X+Y = 22+12 = 34 (Answer).