$\frac{Z-M}{M-\bar{x}}=\ldots \ldots \ldots \ldots$

For the following data,the modal class is .... .

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$
Frequency	$7$	$16$	$25$	$32$	$20$

Find the mean,median and mode of the following frequency distribution:

Class	$30-40$	$40-50$	$50-60$	$60-70$	$70-80$	$80-90$	$90-100$
Frequency	$5$	$7$	$12$	$10$	$8$	$6$	$2$

In a frequency distribution,the modal class is $70-85$ with frequency $25$. The frequencies of the classes succeeding and preceding the modal class are $20$ and $8$ respectively. Then,the values of $f_{0}, f_{1}$ and $f_{2}$ are respectively.

For a given frequency distribution,the total frequency is $25$ and $\Sigma f_{i} x_{i} = 120$. Then,the mean is $\ldots$

In the formula $\bar{x} = A + \frac{\Sigma f_{i} u_{i}}{\Sigma f_{i}} \times c$,$c$ represents .......