Measures of central tendency

A factory is operating in two shifts, day and night, with 70 and 30 workers respectively. If per day mean wage of the day shift workers is ₹ 54 and per day mean wage of all the workers is ₹ 60, then per day mean wage of the night shift workers (in ₹) is :

In a set of $2n$ distinct observations, each of the observation below the median of all the observations is increased by 5 and each of the remaining observations is decreased by 3. Then the mean of the new set of observations :

Let $\bar X$ and M.D. be the mean and the mean deviation about $\bar X$ of n observations $x_i$, $i=1,2,\dots,n$. If each of the observations is increased by 5, then the new mean and the mean deviation about the new mean, respectively, are :

Let $\bar x$, M and $\sigma^2$ be respectively the mean, mode and variance of n observations $x_1,x_2,\dots,x_n$ and $d_i=-x_i-a$, $i=1,2,\dots,n$, where a is any number.

Statement I : Variance of $d_1,d_2,\dots,d_n$ is $\sigma^2$.

Statement II : Mean and mode of $d_1,d_2,\dots,d_n$ are $-\bar x-a$ and $-M-a$, respectively