Hi,
I was hoping someone else would answer this, but alas.
So far, I have this.
For 1 or 2 adults, always 1
For each kid 16 or over, regardless of gender, always 1
For 1 kid under 16, regardless of gender or under 10, always 1
For 3 kids under 16, regardless of gender or under 10, always 2
For 5 kids under 16, regardless of gender or under 10, always 3
For 2 kids under 16, usually 1, sometimes 2
For 4 kids under 16, usually 2, sometimes 3
I can do the formula for 2 kids under 16, but 4 kids under 16 is huge, and I
can't seem to simplify it, except by using lots of helper cells.
You made any progress?

Regards - Dave.