The average of the boys in a class is $16\, years$ and that of girls is $15\, years.$ The average age for the whole class is

The mean of $100$ items was $46 .$ Later on it was discovered that an item $16$ was misread as $61$ and another item $43$ was misread as $34 .$ It was also found that the number of items twas $90$ and not $100 .$ Then what is the correct mean?

The average age of a group of $18$ persons is $32$ $years$ and $6 \,months.$ If two persons of age $65\, years$ each and one person of age $50\, years$ leave the group, the average age of the remaining persons in the group will be (in $years$)

The mean marks of $10$ boys in a class is $70 \%$, whereas the mean marks of $15$ girls is $60 \%$. The mean marks of all the $25$ students is

The average of two numbers $A$ and $B$ is $20 ,$ that of $B$ and $C$ is $19$ and of $C$ and $A$ it is $21 .$ What is the value of $A ?$

In a $20$ over match, the required run rate to win is $7.2 .$ If the run rate is $6$ at the end of the $15^{th}$ over, the required run rate to win the match is