Answer
a) $\eta=81.9\%$
b) $T_{2,s}=505.5\ K$
Work Step by Step
From table A-17:
Inlet ($T_1=300\ K$): $P_{r1}=1.386,\ h_1=300.19\ kJ/kg$
Outlet ($T_2=550\ K$): $h_{2,a}=554.74\ kJ/kg$
$\dfrac{P_{r2}}{P_{r1}}=\dfrac{P_{2}}{P_{1}},\quad P_1=95\ kPa,\ P_2=600\ kPa$
$P_{r2}=8.754\overset{\small\mbox{A-17}}{\rightarrow}h_{2,s}=508.72\ kJ/kg,\ T_{2,s}=505.5\ K$
$\eta=\dfrac{h_{2,s}-h_1}{h_{2,a}-h_1}$
$\eta=81.9\%$
