A photographer is taking photographs.
She has to arrange the people in two rows one behind the other in order of height.
Each person at the back must be taller than the person directly in front of them.
Along the rows the heights must increase from left to right.
How many different arrangements are there for the photo if there are four people in the group?
In how many ways can 2 basketball teams of 5 players (10 people) be arranged like this for a photo to be taken?
If you want a big challenge you could look for the number of arrangements for twelve people, or any given even number.
This problem is adapted from the NRICH task One Basket with permission of the University of Cambridge. All rights reserved.