Three liquids of densities $d$,$2d$,and $3d$ are mixed in equal proportions of weights. The relative density of the mixture is

If two liquids of same masses but densities $\rho_1$ and $\rho_2$ respectively are mixed,then the density of the mixture is given by:

$A$ $U$ tube with both ends open to the atmosphere is partially filled with water. Oil,which is immiscible with water,is poured into one side until it stands at a distance of $10\, mm$ above the water level on the other side. Meanwhile,the water rises by $65\, mm$ from its original level (see diagram). The density of the oil is ......... $kg/m^3$.

Density of ice is $\rho$ and that of water is $\sigma$. What will be the decrease in volume when a mass $M$ of ice melts?

Mountaineers suffer from nose bleeding (epistaxis) at higher altitudes. Explain.

Pressure at the bottom of a tank of water is $3P$,where $P$ is atmospheric pressure. If water is drawn out till the level of water is lowered by one-fifth,then the pressure at the bottom of the tank is