Let
#E_R->"Average Energy of Reactants"#
#E_P->"Average Energy of Products"#
#E_T->" Energy of Transition State"#
#E_"Af"->"Activatiom Energy of Forward Reaction"#
#E_"Ab"->"Activatiom Energy of Backward Reaction"#
#E_"Af"=E_T-E_R#
#E_"Ab"=E_T-E_P#
#"Enthalpy change of reaction"#
#DeltaH=E_P-E_R=(E_T-E_R)-(E_T-E_p)#
#=E_"Af"-E_"Ab"=(150-250)kJ=-100kJ#
#DeltaH# of reaction being negative the reaction is endothermic.