Calories Burned When Exercising

TheCountryLife

I burned 489 calories doing 60 minutes of "Walking, 4.5 mph, very, very brisk pace" &
a friend burned 357 calories doing 60 minutes of "Walking, 4.5 mph, very, very brisk pace"

Why did I burn 132 more calories then her, when we did the same exact exercise ? Does
it go by what you weigh to determine what your burning in calories ??