$12 \%$ of Kaushal's monthly salary is equal to $16 \%$ of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs.\, 1.08$ lakhs,what is Kaushal's monthly salary in $Rs.$?

The average temperature of the first $4 \, \text{days}$ of a week is $38.6^{\circ} \text{C}$ and that of the last $4 \, \text{days}$ is $40.3^{\circ} \text{C}$. If the average temperature of the entire week is $39.1^{\circ} \text{C}$, find the temperature on the $4^{th} \, \text{day}$ (in $^{\circ} \text{C}$).

If the average of $m$ numbers is $n^{2}$ and that of $n$ numbers is $m^{2}$,then the average of $(m + n)$ numbers is

The mean weight of $34$ students of a school is $42 \, kg$. If the weight of the teacher is included,the mean weight increases by $400 \, g$. Find the weight of the teacher (in $kg$).

$10$ years ago,the average age of all $25$ teachers of a girls' college was $45$ years. $4$ years ago,the principal retired at the age of $60$ years. One year later,a new principal aged $54$ years was recruited. Considering the principal as a teacher,what is the present average age of all $25$ teachers?

$A, B, C$ and $D$ are four consecutive odd numbers and their average is $42$. What is the product of $B$ and $D$?