If the mean of $n$ observations $1^2, 2^2, 3^2, \dots, n^2$ is $\frac{46n}{11}$,then what is the value of $n$?

Let $M$ denote the median of the following frequency distribution. Then $20M$ is equal to:

Class	$0-4$	$4-8$	$8-12$	$12-16$	$16-20$
Frequency	$3$	$9$	$10$	$8$	$6$

If the mean of five observations $x, x + 2, x + 4, x + 6$,and $x + 8$ is $11$,what is the mean of the last three observations?

The following data gives the distribution of height of students. The median of the distribution is:

Height (in $cm$)	$160$	$150$	$152$	$161$	$156$	$154$	$155$
No of students	$12$	$8$	$4$	$4$	$3$	$3$	$7$

If for some positive $x \in R$,the frequency distribution of the marks obtained by $20$ students in a certain test is as follows:

Marks	$2$	$3$	$5$	$7$
Frequency	$(x+1)^2$	$2x-5$	$x^2-3x$	$x$

Then the mean of the marks is:

In a class of $100$ students,there are $70$ boys whose average marks in a subject are $75$. If the average marks of the complete class are $72$,then what are the average marks of the girls?