The variance of $50$ observations is $7$. If each observation is multiplied by $6$ and then $5$ is subtracted from it,then the variance of the new data is

$A$ horizontal uniform glass tube of $100 \ cm$ length, sealed at both ends, contains a $10 \ cm$ mercury column in the middle. The initial temperature and pressure of air on either side of the mercury column are $31^{\circ} C$ and $76 \ cm$ of mercury, respectively. If the air column at one end is kept at $0^{\circ} C$ and the other end at $273^{\circ} C$, then the pressure of the air at $0^{\circ} C$ is (in $cm$ of $Hg$):

One die and a coin (both unbiased) are tossed simultaneously. The probability of getting $5$ on the top of the die and tail on the coin is

In which of the following is the hydration energy higher than the lattice energy?

Arrange the proper pair.

Column-$I$	Column-$II$
$(a)$ Land snail	$(1)$ Urea
$(b)$ Cartilaginous fishes	$(2)$ Uric acid
$(c)$ Marine fishes	$(3)$ Ammonia

The proton and neutron are collectively called as