ELI5: Explain Like I'm 5

One in ten rule

Imagine you are in a big school with a lot of students. Let's say there are 1000 students in your school.

Now, let's say that one day your teacher tells you that out of all of the students in your school, only 10% or one out of every ten students is allowed to do a certain activity. For example, let's say only one out of every ten students can ride on a fancy school bus to a field trip.

So, if you count the students in your class, and there are 30 students, how many students get to ride on the fancy school bus? You would take 10% of 1000 students (100) and divide it by 10 (since there is one bus and it holds 10 students), which means only 10 students in your entire school can ride the bus.

Since there are 30 students in your class, you would divide 30 by 10 (the number of students the bus holds) which means only 3 students out of the entire class can go on the fancy school bus.

This is what the "one in ten" rule means - that only one out of every ten students is allowed to do certain things or participate in certain activities. It's important to remember that not everyone will always get to do everything they want, but it's okay because everyone will get a turn eventually.