Qualcomm interview questions

Some basic probability/stochastic process questions about lossy wireless channels. The last question the interview asked was: "Suppose we make 10 packet transmissions per second over a wireless channel, the channel is lossy such that with probability 1/10 a packet transmission will fail. The transmitter knows perfectly whether a transmission succeeds or fails. When it fails, the transmitter retransmit the packet, until it finally succeeds. So what is the throughput we can get?" This was a VERY VERY simple question that the throughput should be 9 packets/second! The interview didn't agree and simply emphasized "because of retransmission, throughput should be reduced more than 1/10" repeatedly. Couldn't achieve a consensus with him after a long debate and that's it.