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

The weights (in $kg$) of $50$ wrestlers are recorded in the following table:

Weight (in $kg$)	$100-110$	$110-120$	$120-130$	$130-140$	$140-150$
Number of wrestlers	$4$	$14$	$21$	$8$	$3$

Find the mean weight of the wrestlers (in $kg$).

The median of the following frequency distribution is $28.5$ and the total frequency is $60$. Find the missing frequencies $x$ and $y$.

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$
Frequency	$5$	$x$	$20$	$15$	$y$	$5$

Calculate the mean of the following data:

Class	$4-7$	$8-11$	$12-15$	$16-19$
Frequency	$5$	$4$	$9$	$10$

The following are the ages of $300$ patients getting medical treatment in a hospital on a particular day:

Age (in years)	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$
Number of patients	$60$	$42$	$55$	$70$	$53$	$20$

Form:
$(i)$ Less than type cumulative frequency distribution.
$(ii)$ More than type cumulative frequency distribution.

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

Class	$0-50$	$50-100$	$100-150$	$150-200$	$200-250$	$250-300$	$300-350$
Frequency	$10$	$15$	$30$	$20$	$15$	$8$	$2$