$T_{x}$ = (512 * 8 ) / (1024 * 10^ 3) = 4 ms
$T_{p}$ = 50 ms
Therefore within this time of transferring one packet in the link and receiving the acknowledgement the time gap is
2 * $T_{p}$ + 4 = 104 ms
within this time the number of packets we can send is 104 /4 =26 in order to fully utilize the link .
Thats what am getting . Correct me if am getting wrong .