Total umber of $60°$ bond angles present in $P_4$are. 

[If your answer is 20, divide ii by 2 hence answer will be 10]

The total number of 60 degree bonds angle in $P_4$ is 12.

The numerical value according to the given condition is,

$$\begin{gathered} = \frac{12}{2} \\ =6 \end{gathered}$$