12 identical rods made of same material are arranged in the form of a cube. The temperature of 'p' and 'r' are maintained at 90 and 30 repsectively. The temperature of 'v' in steady state is

 12 identical rods made of the same material are arranged in the form of a cube. The temperature of ‘p’ and ‘r’ are maintained at 90 °C and 30 °C respectively. The temperature of ‘v’ in steady-state is

(a) 60 °C
(b) 65 °C
(c) 50 °C
(d) 20 °C

Answer: (b) 65 °C