The Equation of Continuity states the mass flow rate has the same value at every position along a tube that has a single entry and a single exit point for fluid flow.
Basically it boils down to the idea that the fluid doesn't disappear or appear from nowhere. If 2.0 kg of fluid flows past a point in a tube in a time of 1.0 s, then 2.0 kg of fluid flows past another point in that tube in 1.0 s as well. If the tube is getting larger or smaller, the velocity adjusts to keep the mass flow rate the same.
For a definition of mass flow rate, check the textbook.
At Location One, fluid with a density of 1.21×103 kg/m3 is flowing at speed of 4.35 m/s through a circular pipe which has a radius of 7.600×10-2 m. As the fluid flows along the pipe, the pipe gets larger. At Location Two the pipe has a radius of 1.702×10-1 m (it is still circular in nature).
What is the cross-sectional area of the pipe at Location One?
What is the speed of the fluid at Location Two?