3 families on holiday together splitting food bill. The families (all related if that makes a difference to how it's approached) are made up as follows:
Family A are 2 adults with a 5 year old child.
Family B are 2 adults with a 20 month old child.
Family C is 1 adult with a 10 year old child.
Alcohol is being worked out separately as not everyone is drinking.
The food bill is currently being split 3 ways between each family.
Is the most fair way of doing things and if not what is?