Given that,
The ratio of shares$:$
- Amal : Sunil $= 3 : 2$
- Sunil : Mita $= 4 : 5$
Now, combining the ratio.
- Amal : Sunill $= (3:2) \times 4 = 12 : 8 $
- Sunil : Mita $= (4:5) \times 2 = 8 : 10 $
$\boxed { \text{Amal} : \text{Sunil} : \text{Mita} = 12 : 8 : 10 = 6 : 4 : 5}$
Let the shares of Amal, Sunil, and Mita be $6x, 4x,$ and $5x.$
Now, $6x – 4x = 400 $
$ \Rightarrow 2x = 400 $
$ \Rightarrow \boxed{x = 200}$
So, the share of Sunil $ = 4x = 4(200) = \text{Rs.}\;800$
$\therefore$ The share of Sunil is $\text{Rs.}\;800. $
Correct Answer $: 800$