The average weight of $A, B$ and $C$ is $45\, kg$. If the average weight of $A$ and $B$ is $40\, kg$ and that of $B$ and $C$ is $43\, kg$,then the weight of $B$ is (in $, kg$)

The mean of $19$ observations is $4$. If one more observation of $24$ is added to the data,the new mean will be

$A$ club has $15$ men and $25$ women. The average age of men is $10 \text{ years}$ and the average age of women is $12 \text{ years}$. What is the average age of the whole club in years?

The average age of a board of directors of a company,having $10$ directors,was $48$ years. Coincidentally,when a director aged $53$ resigned from the board,another director died on the same day. $A$ new director aged $34$ joined the board. Next year in the same month,the average age of all the $9$ directors was found to be $46$ years. The age of the late (i.e.,dead) director at the time of his death was (in years):

The average age of $30$ women decreases by $3$ months if a new person,Neha,is included in place of a $25$ year old woman. Calculate the age of Neha in years.

The average salary of all the associates in a team is $Rs. 16000$. The average salary of $7$ senior associates is $Rs. 24000$ and the average salary of the rest is $Rs. 12000$. How many associates work in that team?