Question

I need Help!!

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

f(x) = 5000(0.4)x, with a horizontal asymptote of y = 0
f(x) = 5000(0.6)x, with a vertical asymptote of x = 0
f(x) = 5000(1.4)x, with a horizontal asymptote of y = 0
f(x) = 5000(1.6)x, with a vertical asymptote of x = 0

Answer 1

f(x) = 5000(0.4)x, with a horizontal asymptote of y = 0

Explanation:

Edge

Answer 2

(x) = 5000(0.4)x, with a horizontal asymptote of y = 0

Explanation:

The function is in the form

y = a b^x

where a is the initial value and b is the growth (or decay rate)

a = 5000 and b = 40 %

(If we have been given 40 % dies off we would have taken 1-40% or 1- .4)

y = 5000 ( .4) ^x

This has a horizontal asymptote at y = 0 because we will never get to 0 bacteria. There will always be part of a bacterial left