`~rai~`
\(\begin{cases}P+E+N=46\quad(1)\\P+E=1,875N\quad(2)\\P=E\quad\quad\quad\quad\quad\quad(3)\end{cases}\\\text{Lấy (1)-(2) được:}\\(P+E+N)-(P+E)=46-1,875N\\\Leftrightarrow P+E+N-P-E=46-1,875N\\\Leftrightarrow N=46-1,875 N\\\Leftrightarrow N+1,875N=46\\\Leftrightarrow 2,875 N=46\\\Leftrightarrow N=16.\\\text{Thay N=16 vào (2) được:}\\P+E=1,875.16\\\Leftrightarrow P+E=30\\\text{Mà theo (3),ta có P=E}\\\Rightarrow P=E=\dfrac{30}{2}=15.\\\text{Vậy (P;E;N)=(15;15;16).}\)
