A vernier scale has $"$A$"$ main scale divisions are coinciding with $"20"$ vernier scale division. And value of $1$ main scale corresponds to $"0\mathrm{.}4"$ mm$.$

The final reading observed is $"3\mathrm{.}14"$ mm$,$ the main scale reading and vernier scale observations are $"2\mathrm{.}8"$ mm and $"17"$ division respectively.

Determine the following:

i$.$ Least count in mm

ii$.$ Value of $1$ vernier scale division.

iii. How much main scale division $("$A$")$ coinciding with $"20"$ vernier scale division.