Answer: 510 m/s
Explanation: specific gravity of steam is 18/29 = 0.620
It is the ratio of the density of steam over density of water
400m3/s of steam =
400m3ms * 0.620 of water
= 248m3/s of water
Total flow rate Q = 248 + 7 = 255m3/s
Using Q = AV
Where A is area and V is velocity
V = Q/A
V = 255/0.5 = 510m/s