@carefulunicorn-0 Yep! As energizedpanda says, the path needs to be on the surface of the figure-- imagine a bug crawling along :). (otherwise the answer for any kind of 3D shape would always be a straight line between the two points!)
@The-Rogue-Blade Your idea is correct but you missed some pairs and also, a<b so pairs with the same numbers are incorrect. When prof. loh drew a line across the chart he did it above the middle, so he excluded all the pairs with the same numbers.
These shouldn't be included️
4: 2,2 1,1
5: 2,2 1,1
6: 3,3 2,2 1,1
7: 3,3 2,2 1,1
I really liked the way you did the question and it would be quite useful if I didn't want to draw a graph