Do p = e nên:
\(\left\{{}\begin{matrix}2p+n=60\\p-n=0\end{matrix}\right.< =>\left\{{}\begin{matrix}p=20\\n=20\end{matrix}\right.\)\(\left\{{}\begin{matrix}2p+n=60\\p-n=0\end{matrix}\right.< =>\left\{{}\begin{matrix}p=20\\n=20\end{matrix}\right.\)
Vậy e = p = n = 20