So this question is just a comparison problem.
If you split a chocolate bar into seven pieces, and ate 5 of them, you would have eaten less than if it were split into 10 pieces and you ate 8.
Another way to see this is if we did it mathematically.
5/7*10/10 = 50/70
8/10*7/7 = 56/70
Now that the denominators are the same, you can compare 50 to 56 and obviously, 50 is smaller than 56.
Hope this helps! If you have any questions, just ask!