Question

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.


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

@kc_kennylau @agent0smith

Answer 2

For any geometric sequence a, ar, ar^2, ar^3, ..., ar^(n-1), we have an explicit formula:
\[\Large a_n=ar^{n-1}\]where \(a_n\) is the \(n\)th term, \(a\) is the first term and \(r\) is the common ratio.

Answer 3

So the answer is either A or C, right?

Answer 4

Is it C?

Answer 5

Perfect :)

Answer 6

Thanks :)

Answer 7

No problem at all! :D