A waste activated sludge (WAS) is to be blended with green waste (GW). The carbon (C) and nitrogen (N) contents, per kg of WAS and GW, on dry basis are given in the table.

$$\begin{array}{|c|c|} \hline\text{Parameter} &\text{WAS} &\text{GW} \\ \hline \text{Carbon (g)} &54 & 360 \\ \hline \text{Nitrogen (g)}& 10 & 6 \\ \hline \end{array}$$
The ration of WAS to GW required up to two decimal places) to achieve a blended $C: N$ ratio of $20:1$ on dey basis is ____