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

The mean weight of $150$ students in a class is $60 \, kg$. The mean weight of boys is $70 \, kg$ and that of girls is $55 \, kg$. What is the number of boys in the class?

Mr. Patel walked $6 \, km$ to reach the station from his house,then he boarded a train whose average speed was $60 \, km/hr$ and thus he reached his destination. In this way,he took a total of $3 \, hours$. If the average speed of the entire journey was $32 \, km/hr$,then the average speed of walking is (in $km/hr$):

The average weight of a group of $20$ boys was calculated to be $89.4 \text{ kg}$ and it was later discovered that one weight was misread as $78 \text{ kg}$ instead of the correct one of $87 \text{ kg}$. The correct average weight is in $\text{kg}$.

The average salary of workers in $AMS$ careers is $Rs. 2,000$,the average salary of faculty is $Rs. 4,000$,and the average salary of management trainees is $Rs. 1,250$. The total number of workers could be:

The average of $12$ results is $15,$ and the average of the first two is $14.$ What is the average of the rest?