First solve the potential energy of the biker. using the fomula: PE = mgh where m is the mass of the object g is the acceleration due to gravity ( 9.81 m/s2) h is the height
PE = 96 kg ( 1120 m ) ( 9.81 m/s2) PE = 1054771.2 J then power = Work / time P = 1054771.2 J / ( 120 min ) ( 60 s / 1 min) P = 146.5 W