Question

students are reading a graph showing bacterial growth in a petri dish as a function of time.
adria says, \there must have been ten bacteria in the petri dish to start.\
celena says, \the number of bacteria started increasing slowly, but gradually it is increasing faster.\
elia says, \the range is the set of all positive real numbers.\
gabi says, \at the two - hour mark, there were 16 bacteria.\
which student is incorrect, and why?
options:

• adria, there is not enough information to tell how many bacteria were there to start
• celena, the number of bacteria started increasing quickly and gradually slowed down
• gabi, at the two - hour mark, there were 12 bacteria
• elia, the range starts at 10 and increases thereafter

Explanation:

First, analyze each student's statement against the graph:

1. Adila: The graph starts at (0,10), so 10 initial bacteria is correct.
2. Chiara: The curve is exponential, so growth speeds up over time; her statement is correct.
3. Eli: The number of bacteria must be positive integers (you can't have a fraction of a bacterium), so the range cannot be all positive real numbers. This makes Eli incorrect.
4. Gabi: Tracing the 2-hour mark on the graph aligns with 16 bacteria, so this is correct.

Answer:

Eli: The range is the set of positive integers (you cannot have a fraction of a bacterium), so the range is not all positive real numbers.