Question

Bruce added some chlorine to the water in a pool. The chlorine evaporated at a fixed rate every week. The table below shows the amount of chlorine f(n), in ounces, that was left in the pool after n weeks:


n f(n)
1 54
2 27
3 13.5
4 6.75


Which function best shows the relationship between n and f(n)?
f(n) = 108(0.5)n − 1
f(n) = 54(0.5)n
f(n) = 108(0.5)n + 1
f(n) = 54(0.5)n − 1