Chang 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:

Question

n f(n)
1 24
2 12
3 6
4 3

Which function best shows the relationship between n and f(n)?
f(n) = 48(0.5)n − 1
f(n) = 24(0.5)n
f(n) = 24(0.5)n − 1
f(n) = 48(0.5)n + 1

Answer 1

well, each week there was 1/2 as much left, right?
online, use ^ for exponents, so it doesn't look like you're just multiplying by n
Also, use parentheses.
0.5^n - 1
is not the same as
0.5^(n-1)

So plug in a couple of values of n and see which formula works.