The Function F $$f ( x ) = 800 ( 0.5 ) ^ { x / 60 }$$

The function f $$f ( x ) = 800 ( 0.5 ) ^ { x / 60 }$$ models the amount in pounds of a particular radioactive material stored in a concrete vault, where x is the number of years since the material was put into the vault. Find the amount of
Radioactive material in the vault after 40 years. Round to the nearest whole number.

A) 267 pounds
B) 600 pounds
C) 283 pounds
D) 504 pounds