What are fluids?

Is pressure a scalar or a vector? Give reason.

Two vessels $A$ and $B$ have the same base area and contain water to the same height,but the mass of water in $A$ is four times that in $B$. The ratio of the liquid thrust at the base of $A$ to that at the base of $B$ is (in $:1$)

Gauge pressure is defined as:

Two liquids having densities $d_1$ and $d_2$ are mixed in such a way that both have the same mass. The density of the mixture is ............

The pressure at half the depth of a lake is equal to two-third pressure at the bottom of the lake. So the depth '$h$' of the lake is ($\rho$ = density of water in the lake, $g$ = acceleration due to gravity, $P_0$ = atmospheric pressure).