The conservation of the mass of fluid through two sections (be they A1 and A2) of a conduit (pipe) or current tube establishes that the mass that enters is equal to the mass that exits. Mathematically the input flow must be the same as the output flow,
[tex]Q_1 = Q_2[/tex]
The definition of flow is given by
[tex]Q =VA[/tex]
Where
V = Velocity
A = Area
The units of the flow of flow are cubic meters per second, that is to say that if there is a continuity, the volume of input must be the same as that of output, what changes if the sections are modified are the proportions of speed.
In this way
[tex]Q_A = Q_B[/tex]
[tex]Q_B = 2.94*10^2 m^3/s[/tex]
