A 10 foot flagpole casts a 4 foot shadow. At the exact time a 15 foot tree casts a shadow. What is the length of the trees shadow?

I would say that the 15 foot tree would cast a 6 foot shadow. I say this because for every 5 feet of an object, it is two inches of a shadow.

5 foot flagpole - 2 foot shadow

10 foot flagpole - 4 foot shadow

15 foot tree - 6 foot shadow