What is the effect on the velocity of fluid if streamlines are widely spaced?

$A$ liquid flows steadily through a cylindrical pipe having a radius $2R$ at point $A$ and radius $R$ at point $B$ farther along the flow direction. If the velocity at point $B$ is $4v$,what will be the velocity at point $A$?

$A$ liquid flows in a tube from left to right as shown in the figure. $A_1$ and $A_2$ are the cross-sections of the portions of the tube as shown. Then the ratio of speeds $v_1/v_2$ will be

$A$ pipe having an internal diameter $D$ is connected to another pipe of the same size. Water flows into the second pipe through $n$ holes,each of diameter $d$. If the water in the first pipe has speed $v$,what is the speed of water leaving the second pipe?

In a streamlined flow,the velocity of a fluid at a given point

$A$ horizontal tube of non-uniform cross-section has radii of $0.2\,m$ and $0.1\,m$ at points $P$ and $Q$ respectively. For the streamline flow of an incompressible liquid,the rate of liquid flow is: