Because they are!!!
It sometimes is for the right reason, but I do 100% agree that it does seem selfish, I would HATE to have to do that!
The answer is 1 and 2/12th first you take the 2/3 into 8/12 and and the 2/4 into 6/12 and then you add them together to get 14/12. Then you simplify is to 1 and 2/12 and 2//12 into 1/6. I hope this helps.
I think the answer is c hope it helps tell me if I'm wrong
