Properties of Solids and Liquids: JEE Main 2026 Physics question

An aluminium and steel rods having same lengths and cross-sections are joined to make total length of 120 cm at 30°C. The coefficient of linear expansion of aluminium and steel are $24\times10^{-6}$ /°C and $1.2\times10^{-5}$ /°C, respectively. The length of this composite rod when its temperature is raised to 100 °C, is ______ cm.