The mean of natural numbers between $1$ to $20$ which are multiples of $3$ is ..........

Mode of the data $15, 14, 19, 20, 14, 15, 16, 14, 15, 18, 14, 19, 15, 17, 15$ is

If $\bar{x}$ is the mean of $x_{1}, x_{2}, \ldots, x_{n},$ then for $a \neq 0,$ the mean of $a x_{1}, a x_{2}, \ldots, a x_{n}, \frac{x_{1}}{a}, \frac{x_{2}}{a}, \ldots, \frac{x_{n}}{a}$ is

Ten observations $6, 14, 15, 17, x+1, 2x-13, 30, 32, 34, 43$ are written in an ascending order. The median of the data is $24$. Find the value of $x$.

The following table gives the frequencies of most commonly used letters $a, e, i, o, r, t, u$ from a page of a book:

Letters	$a$	$e$	$i$	$o$	$r$	$t$	$u$
Frequency	$75$	$125$	$80$	$70$	$80$	$95$	$75$

Represent the information above by a bar graph.

The range of the observations: $7, 9, 7, 5, 6, 6, 9, 18, 8, 8, 6$ is ..........