Two metal rods with the same geometry but made of different metals are welded togather. the thermal conductivities are 0.4 for the material on the left and 0.9 J/(k.m.s) for the material on the right. The leftmost end is held at a temperature of 300 and the rightmost end is held at 500 K. What is the temperature in the middle where the two rods meet?
a) 361.5 K
b) 400.0 K
c) 325.5 K
d) 438.5 K