Answer:
assume nitrogen is an ideal gas with cv=5R/2
assume argon is an ideal gas with cv=3R/2
n1=4moles
n2=2.5 moles
t1=75°C  in kelvin t1=75+273
t1=348K
T2=130°C  in kelvin t2=130+273
t2=403K
u=пCVΔT
U(Nâ‚‚)+U(Argon)=0
putting values:
=>4x(5R/2)x(Tfinal-348)=2.5x(3R/2)x(T final-403)
by simplifying:
Tfinal=363K