Question 1070037
.
you need to separate the population of 27 students (27 = 28-1, this 1 is Tom) in two disjoint groups in a way that population 
of the larger group is two times the population of the smaller group.



These groups are 9 and 18 students:


x + 2x = 27 


gives 3x = 27 and x = 9, 


so Tom is in 10-th position.