I think a common utilitarian way of thinking is years of life left. A baby has a far greater expected value of remaining years and thus is often assigned higher moral value by people. For me it was a no-brainer to kill the old people, although I was imagining them as very old such that they each only had ~5 years left on average.
Mostly agreed. But in another society that values the wisdom of their elders, then they could see that as a large loss. Where-as the baby is replaceable with very little cost to society. I wonder if the stats would be different in an Eastern society.
I think of it from more of an anti-natalist perspective. The child will have a far greater chance of suffering while the adults will have a chance for less suffering due to their expected lifespan. That’s why I thought about it in the frame of abortion. We’ll typically assign the notion of having a life positive value, but from my perspective that’s just a chance for more suffering.
I chose to read it as "would you kill a teenager, or all of that teenager's caregivers." I felt that sufficiently raised the moral stakes, to make both choices similarly hazardous, while fitting into the parameters written into the scenario.