Chemical Kinetics And Nuclear Chemistry

For a reaction taking place in three steps at same temperature, overall rate constant \(\mathrm{K}=\frac{\mathrm{K}_1 \mathrm{~K}_2}{\mathrm{~K}_3}\). If \(\mathrm{Ea}_1, \mathrm{Ea}_2\) and \(\mathrm{Ea}_3\) are 40, 50 and \(60 \mathrm{~kJ} / \mathrm{mol}\) respectively, the overall \(\mathrm{Ea}\) is ________ \(\mathrm{kJ} / \mathrm{mol}\).