It will be both of the girls burn the same amount of calories because 450/2 will give you 225 then you divide 620/2 you'll get 310. If you add 225+310, it will give you 535. That is for Carly. Then if you do 560/2, it will give you 280 then you divide 510 by 2, you'll get 235. 280+235= 535. That is for Sarah. As you can see, they are both the same results. I hope this is right!