Natural and human-made substances break down over time and figuring out how much is left over time is very common. The function A(t)=135(.917)t

Question

represents the amount of substance, A(t)
, given the number of days, t
. How much of the substance will be left after 18 days, to the nearest whole value? Find A(18)
. (1 point)
Responses

30
30

25
25

29
29

28

Answer 1

25

To find A(18), we substitute t=18 into the function A(t)=135(.917)^t:

A(18) = 135(.917)^18
A(18) ≈ 135(0.2293)
A(18) ≈ 30.963

Rounded to the nearest whole number, A(18) is approximately 31 units of substance left after 18 days.