Find the Total Pressure When the Faucet is Released

[![enter image description here](https://i.stack.imgur.com/Sx0Vw.png)](https://i.stack.imgur.com/Sx0Vw.png)
Two chambers are connected as shown in the figure. The total pressure of the first chamber that contains Ar and He gas is 98.4 atm. If the faucet is released, find the total pressure. (There's 1 mol of Nitrogen gas on the second chamber)


(A) 52.2 atm (B) 61.5 atm (C)98.4 atm (D)123 atm (E)172.2 atm


My attempt:


Because of Ar and He are inert gas I only calculate the second chamber's partial pressure.


$$\begin{aligned}
P\_2&=\frac{1\cdot0.082\cdot300}{1}\\
&=24.6\mbox{ atm}\\\\
P\_{tot}&=P\_1+P\_2\\&=123\mbox{ atm}\\\\
\end{aligned}$$
My other attempt:
$$\begin{aligned}
n\_2&=\frac{1\cdot98.4}{0.082\cdot300}\\
&=4\mbox{ mol}\\\\
n\_{tot}&=n\_1+n\_2\\&=5\mbox{ mol}\\\\
P\_{total}&=\frac{5\cdot0.082\cdot300}{2}\\&=61.5\mbox{ atm}
\end{aligned}$$


My question is which one is the correct method and why.


