IKMC 2009 - Grades 11-12 - Paper 02 - Self-study Question 12

There are 2009 kangaroos, each light or dark. One light kangaroo is taller than exactly 8 dark kangaroos, one than exactly 9, one than exactly 10, and so on, with exactly one taller than all dark kangaroos. How many are light?

Intended reading: this consecutive list accounts for all light kangaroos.