A broad gauge railway line passes through a horizontal curved section (radius $=875 \:m$) of length $200 \: m$. The allowable speed on this portion is $100 \: km/h$. For calculating the cant, consider the gauge as centre-to-centre distance between the rail heads, equal to $1750 \: mm$. The maximum permissible cant (in $mm$, round off to $1$ decimal place) with respect to the centre-to-centre distance between the rail heads is _____________