The solid of Problem 3-74 is initially uniform in temperature at 100C, but suddenly the two surfaces

The solid of Problem 3-74 is initially uniform in temperature at 100ºC, but suddenly the two surfaces are lowered to 0 and 40ºC. If the solid has k = 20 W/m·ºC and α = 5 × 10−6 m2/s, find the steady-state temperature of each node and the nodal temperatures after 1 min.