Answer
$\mathcal{V}_2=184.1\ m/s$
Work Step by Step
From table A-6:
Inlet ($P_1=150\ kPa, T_1=120°C$): $s_1=7.2699\ kJ/kg.K,\ h_1=2711.4\ kJ/kg$
Outlet ($P_2=300\ kPa, s_2=s_1$): $h_2=2845.7\ kJ/kg$
From the energy balance:
$\dot{m}(h_1+\mathcal{V}_1^2/2)=\dot{m}(h_2+\mathcal{V}_2^2/2)$
$h_1+\mathcal{V}_1^2/2=h_2+\mathcal{V}_2^2/2$
Given $\mathcal{V}_1=550\ m/s$ and solving for the outlet velocity
$\mathcal{V}_2=184.1\ m/s$
