The Table below shows the collected field data for setting out a drainage. If at chainage $0+10,$ the invert reduced level was $598\mathrm{.}92$ m $,$ and meanwhile, the drainage was designed with a rising grade of $1$ in $200$ from chainage $0+10$ to $0+76.$ Calculate the following:

a$.$ The invert levels at all the chainages $|10|$ marks

b$.$ The height of the sight rails at $0+10,0+30$ and $0+76$ if the boning rod is $2$ m long. $10$ marks

c$.$ The depth to be excavated at all the chainages.

$5$

marks

Chainage $($m$)$ Ground reduced levels

$\backslash$table$[[,(m)$