$7.$ Consider a network with only a single switch shared by $2$ clients. The available bandwidth of both links are $10$ Mbps as follows:

$7$a$.$ Assume that $(1)$ the switch has an infinitely large buffer, $(2)$ TCP timeout set to infinite, $(3)$ reverse feedback channel is reliable and $(4)$ retransmission can always be successful. Say the curve of the right figure is the achievable throughput when the end$-$to$-$end packet error probability of the forward path is $25\%.$ Then what is the maximal achievable throughput R$$ of each client?