Whenever a packet is transmitted immediately the next packet will start getting transmitted. It is not like packet 1 will reach the destination then only packet 2 will start getting transmitted. It will not even wait for propagation.
Here, A started transmitting packet 1 ao time = 0. At time = 1 the transmission finishes and packet 1 starts propagating.
At time t = 1 (when A finishes transmitting Packet 1) A starts transmitting packet 2. Please see the above diagram you will understand. Notice that P1 reaches B at t= 98. and then every next millisecond B is receiving one packet.
So the message will be fully reached the destination at ( 98 (when 1st packet reaches) + 99 (rest 99 packets reach one every one millisecond) ) = 197 mSec.