Question

For breakfast, Randy had two Egg

Answer 1

Since the only difference in the two meals is one egg mcmuffin, then the difference in the calorie count has to be due to the mcmuffin.  So

750 - 450 = 300 calories for an egg mcmuffin.

Jack's egg mcmuffin and hashbrowns totaled 450 calories.  Since we know that an egg mcmuffin is 300 calories, then the hashbrowns have to be

450 - 300 = 150 calories