A brass rod 12.0 cm long, a copper rod 18.0 cm long, and an aluminum rod 24.0 cm long—each with cross-sectional area 2.30 cm³ are welded together end to end to form a rod 54.0 cm long, with copper as the middle section. The free end of the brass section is maintained at 100.0°C, and the free end of the aluminum section is maintained at 0.0°C. Assume that there is no heat loss from the curved surfaces and that the steady-state heat current has been established. What is

(a) The temperature T₁ at the junction of the brass and copper sections;

(b) The temperature T₂ at the junction of the copper and aluminum sections;

(c) The heat current in the aluminum section?