Compute the rate of heat transfer through the wall

Question

Solve the below problem:

Q: As shown in Fig. the 6-in-thick exterior wall of a building has an average thermal conductivity of 0.32Btu/h · ft · oR. At steady state, the temperature of the wall decreases linearly from T1 = 70^oF on the inner surface to T2 on the outer surface. The outside ambient air temperature it T0 = 25^oF and the convective heat transfer coefficient is 5.1Btu/h ·ft2 ·oR. Determine

(a) The temperature T2, in oF, and

(b) The rate of heat transfer through the wall, in Btu/h per ft2 of surface area.