Question

Midge 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 16
2 8
3 4
4 2


Which function best shows the relationship between n and f(n)?
f(n) = 16(0.5)n − 1
f(n) = 32(0.5)n − 1
f(n) = 16(0.5)n
f(n) = 32(0.5)n + 1

Answer 1

f(n) = 16(0.5)ⁿ⁻¹

Explanation:

Find f(1) for each option.

a) f(1) = 16(0.5)¹⁻¹ = 16

b) f(1) = 32(0.5)¹⁻¹ = 32

c) f(1) = 16(0.5)¹ = 8

d) f(1) = 32(0.5)¹⁺¹ = 8

Only the first option matches the table.