If $3 \bar{x} = 2 M = 60,$ then $Z = \dots$

The median of the following frequency distribution is $49$ and the total frequency is $100$. Find the missing frequencies $x$ and $y$.

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$	$70-80$
Frequency	$2$	$6$	$8$	$x$	$20$	$18$	$y$	$14$

Find the median of the following frequency distribution:

Class	$60-70$	$70-80$	$80-90$	$90-100$	$100-110$	$110-120$
Frequency	$5$	$15$	$20$	$30$	$20$	$8$

In the formula $Z = l + \left( \frac{f_{1} - f_{0}}{2f_{1} - f_{0} - f_{2}} \right) \times c$ for the mode,$c = \dots$

The mode of the observations $4, 5, 6, 3, 4, 3, 3, 2, 3, 5$ is $\ldots \ldots \ldots \ldots .$

If $M - \bar{x} = 2$ and $Z = 20.5$,then the median $M = \ldots$ (in $.5$)