The velocity of efflux of a fluid through an orifice $15 \mathrm{cm}$ below the fluid surface (which is open to the atmosphere) is [Take $g=10{ \mathrm{ms}}^{-2}$]

In the figure shown below, a fluid of density $2\times {10}^3 \mathrm{kg}{ \mathrm{m}}^{-3}$ is flowing in a horizontal pipe. The speed of water at point $A$ is $4 \mathrm{cm}{ \mathrm{s}}^{-1}$, what is its speed at point $B?$

A vessel is filled with two different liquids of densities $\mathrm{\rho }$ and $2\mathrm{\rho }$ respectively as shown in the figure. The velocity of flow of liquid through a hole at height $\frac{h}{2}$ from bottom is