Here in this question it is not given whether polling is used for first node or first node start transmission without polling as polling definition given above is here is a polling delay of 8080 μs to poll the next node
if we start polling from first node then question has been already answered--
but in case it starts from first node then total channel efficiency = 10*transmission time/(10*transmission time + 9*polling time) = 100/109
throughput = eff * B = 10*(100/109) ~ 100/11
please let me know if i am wrong somewhere