A first order reaction is 50% completed in 20 min at 27 degree celsius and in 5 min at 47 degree celsius

A first order reaction is 50% completed in 20 min at 27 degree celsius and in 5 min at 47 degree celsius. The energy of activation of the reaction is :

a) 43.85 KJ/mol
b) 55.3 KJ/mol
c) 11.97 KJ/mol
d) 6.65 KJ/mol

Answer : b) 55.3 KJ/mol

energy-reaction