$5$ marks

A composite wall is shown in Figure P$13-8.$ For element $1,$ let $K_{}=5\frac{W}{m-C},$ for element $2$ let $K_{}=10\frac{W}{m-C},$ for element $3$ let $K_{}=15\frac{W}{m-C}.$ The left end has a heat source of $600$ W applied to it$.$ The right end is held at $10C.$ Determine the left end temperature and the interface temperatures and the heat flux through element $3.$