Question

A scientist measures the amount of bacteria in a Petri dish daily for 4 days and then discards the bacteria sample. The scientist finds that this growth is described by the function
A
(
d
)
=
4
d
+
18
, where A is the amount of bacteria and d is number of days. The graph that represents this situation is shown below.



image.png



Select the domain for the function that represents the amount of bacteria in the dish as a function of time, in days.


real numbers from 1 to 4


all real numbers


real numbers from 0 to 4


real numbers from 20 to 280

Answer 1

Real numbers from 0 to 4.

Reason: time (days) cannot be negative and the experiment lasted 4 days, so d is between 0 and 4 (inclusive). The other choices are invalid (not all reals, 1–4 excludes day 0, and 20–280 are output values, not days).