Which one of the following measures of central tendency is the most suitable for evaluating the intelligence of students based on their marks?

Find the mean of the following frequency distribution:

$x_i$	$5$	$15$	$25$	$35$	$45$	$55$
$f_i$	$12$	$18$	$27$	$20$	$17$	$6$

The arithmetic mean of the following discrete data $12, 14, 20, 23, 25, 32$ is given by

For a distribution $x_1, x_2, \dots, x_{101}$ such that $x_1 < x_2 < x_3 < \dots < x_{100} < x_{101}$,the mean deviation of this distribution about a number $k$ is minimum. Then $k$ is equal to which of the following?

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?

What is the weighted mean of the first $n$ natural numbers if the weights are equal?