Compute the correct answer of the following question

Question- A very common form of heat exchanger is the shell and tube type. In the figure below we show a 1-2 fixed head heat exchanger. The tubes are 20 ft long, made of copper. Look up in literature the linear expansion coefficient for copper and calculate the increase in pipe length from room temperature conditions (298K) if the average temperature during operation is 240 and the pipes are free to expand. The outer shell is made of carbon steel and it is also 20 ft in length. You also need to look up the linear expansion coefficient for carbon steel. Since the pipes are attached to the shell via the mantle, they cannot thermally expand independently from each other. We will approach the problem in steps.

Part 1- Calculate the total length of a tube if it was free to expand. Call this length Lt.

Part 2- Calculate the length of the shell if it was free to expand - assume the same temperature change. Call this length Ls.

I want experts assist to determine the change in length of the shell.