isnt it $1.$ At t$=1,$ which packet is sent out? Give the packet number. Queue at t$=1$ Packet $1->$ Class $3->$ arrived at t$=0\mathrm{.}36$ Packet $2->$ Class $3->$ arrived at t$-0\mathrm{.}8$ Since both packets belong to Class $3($the lowest priority class$),$ the round$-$robin scheduler will serve the packet that arrived first. Packet $1$ arrived before Packet $2,$ so Packet $1$ is scheduled for transmission at t$=1.2.$ At t$=2,$ which packet is sent out? Give the packet number. The packet sent is $2$ Queue At t$=2$: Packet $2($Class $3)->$ arrived at t$=0\mathrm{.}8,$ as it had not been sent before. Packet $3($Class $3)->$ arrives at t$=1\mathrm{.}24$ Packet $4($Class $3)->$ arrives at t$=1\mathrm{.}9$ All packets in the queue are classified as Class $3.$ Packet $2,$ which arrived first at t $=0\mathrm{.}8,$ is chosen for transmission. $3.$ At t$=3,$ which packet is sent out? Give the packet number. At time t$=3$ the packet sent is $5$ Queue At t$=3$: Packet $3($Class $3)->$ arrived at t$=1\mathrm{.}24$ Packet $4($Class $3)->$ arrived at t$=1\mathrm{.}91$ Packet $5($Class $2)->$ arrived at t$=2\mathrm{.}49$ Packet $5$ belongs to Class $2,$ which has a higher priority than Class $3$ packets, so it is selected for transmission. $4.$ At t$=4,$ which packet is sent out? Give the packet number. At time t$=4,$ the packet sent is $6$ Queue At t$=4$: Packet $3($Class $3)->$ arrived at t$=1\mathrm{.}24$ Packet $4($Class $3)->$ arrived at t$-1\mathrm{.}91$ Packet $6($Class $2)->$ arrived at t$=3\mathrm{.}3$ Packet $6,$ belonging to Class $2,$ is selected due to its higher priority. $5.$ At t$=5,$ which packet is sent out? Give the packet number. At time t$=5,$ the packet sent is $3$ Queue at t$=5$: Packet $3($Class $3)->$ arrived at t$=1\mathrm{.}24$ Packet $4($Class $3)->$ arrived at t$=1\mathrm{.}91$ Packet $7($Class $3)->$ arrived at t$=4\mathrm{.}13$ The scheduler selects the earliest$-$arrived packet in Class $3,$ which is Packet $3.6.$ At t$=6,$ which packet is sent out? Give the packet number. At time t$=6,$ the packet sent is $8$ Queue At t$=6$: Packet $4($Class $3)->$ arrived at t$=1\mathrm{.}91$ Packet $7($Class $3)->$ arrived at t$=4\mathrm{.}13$ Packet $8($Class $2)->$ arrived at t$5\mathrm{.}08$ Packet $9($Class $2)->$ arrived at t$=4\mathrm{.}13$ Packet $8,$ belonging to Class $2,$ has higher priority and was the earliest to arrive, so it is selected. $7.$ At t$=7,$ which packet is sent out? Give the packet number. At time t$=7,$ the packet sent is $9$ Queue At t$=7$: Packet $4($Class $3)->$ arrived at t$=1\mathrm{.}91$ Packet $7($Class $3)->$ arrived at t$=4\mathrm{.}13$ Packet $9($Class $2)->$ arrived at t$=5\mathrm{.}92$ Packet $9,$ belonging to Class $2,$ is selected because it has a higher priority. $8.$ At t$=8,$ which packet is sent out? Give the packet number. At time t$=8,$ the packet sent is $4$ At t$=8$: Packet $4($Clasc $3)->$ arrived at t$=1\mathrm{.}91$ Packet $7($Class $3)->$ arrived at t$=4\mathrm{.}13$ Packet $4,$ belonging to Class $3,$ is selected because the round$-$robin scheduler is now choosing from Class $3,$ and it was the earliest to arrive among the Class $3$ packets, including Packet $7.9.$ At t$=9,$ which packet is sent out? Give the packet number At time t$=9,$ the packet sent is $7$ At t$=9$ : Packet $7($Class $3)->$ arrived at t$=4\mathrm{.}13$ Packet $7,$ belonging to Class $3,$ is selected because it is the only remaining packet in the queue.