Question

A population of bacteria is treated with an antibiotic. It is estimated that 5,000 live bacteria existed in the sample in

before treatment. After each day of treatment, 40% of the sample remains alive. Which best describes the graph of
the function that represents the number of live bacteria after x days of treatment?

Answer 1

The correct option is A.

Step by step explanation:

The exponential function is defined as

Where, a is initial value and b is growth factor or decay factor.

The initial population of bacteria is 5000.

After each day of treatment, 40% of the sample remains alive. It means the growth factor or decay factor is

Therefore the required function is

The horizontal asymptote is y=0 because

Therefore option A is correct.

Answer 2

The answer is A. f(x) = 5000(0.4)x, with a horizontal asymptote of y = 0, because 2,000 of the bacteria remain alive.

Explanation: