A hanger is made of two bars of different sizes. Each bar has a square cross-section. The hanger is loaded by three point loads in the mid-vertical plane as shown: the upper bar is $100\, \text{mm}\times100\, \text{mm}$ and the lower bar is $50\, \text{mm}\times50\, \text{mm}$. Ignore self-weight and stress concentration. What is the maximum tensile stress (in N/mm$^2$) anywhere in the hanger?