Okay, imagine there's a big group of people who have to decide on something really important, like what kind of cake to make for a party. But some people are older and some are younger, and they might have different opinions because they've experienced things differently in life.
Demeny voting is a way to make sure that everyone's opinion is counted fairly, no matter how old they are. So instead of just one person getting to vote, everyone gets to vote but their vote weighs differently based on their age.
For example, let's say the group has 10 people and half of them are under 18 and half are over 18. Each person's vote is worth one point, except for the older people whose votes are worth more points because they've been around longer and have more experience. So maybe someone who is 50 years old gets 5 points for their vote, while someone who is 10 years old only gets 1 point.
This way, everyone gets a say in the decision but the older people's opinions are still valued because they have more knowledge and experience. It's like a fairness scale - everyone gets a piece of the cake, but some pieces are bigger than others based on how much someone has lived or experienced.