How do you calculate the exit velocity in aerodynamics?

[freedevil]

Homework Statement

Given: Inlet area = 23 ft², Inlet velocity = 107 ft/sec, Exit area = 12 ft². Find exit velocity

The Attempt at a Solution

I am having a hard time solving this. Can someone explain how to do this? Thanks

 

[freedevil]

solved!

Mach number = 107/1116 = 0.0959
This is less than 0.3 so the flow is incompressible

(volumetric flow)in = (volumetric flow)out
(velocity)in x (Cross-sectional Area)in = (velocity)out x (Cross-sectional Area)out
107 x 23 = (velocity)out x 12
(velocity)out = 205 ft/s