If the pond has a radius of 6.5 ft how much fencing will he need

The number of bacteria after t hours is given by N(t)=250 e^0.15t a) Find the initial number of bacteria and the rate of growth

Art [367]

Answer:

a) $N_0=250\; k=0.15$

b) 334,858 bacteria

c) 4.67 hours

d) 2 hours

Step-by-step explanation:

a) Initial number of bacteria is the coefficient, that is, 250. And the growth rate is the coefficient besides “t”: 0.15. It’s rate of growth because of its positive sign; when it’s negative, it’s taken as rate of decay.

Another way to see that is the following:

Initial number of bacteria is N(0), which implies $t=0$ . And $N(0)=N_0$ . The process is:

$N(t)=250 e^{0.15t}\\N(0)=250 e^{0.15(0)}\\ N_0=250e^{0}\\N_0=250\cdot1\\ N_0=250$

b) After 2 days means $t=48$ . So, we just replace and operate:

$N(t)=250 e^{0.15t}\\N(48)=250 e^{0.15(48)}\\ N(48)=250e^{7.2}\\N(48)=334,858\;\text{bacteria}$

c) $N(t_1)=4000; \;t_1=?$

$N(t)=250 e^{0.15t}\\4000=250 e^{0.15t_1}\\ \dfrac{4000}{250}= e^{0.15t_1}\\16= e^{0.15t_1}\\ \ln{16}= \ln{e^{0.15t_1}} \\ \ln{16}=0.15t_1 \\ \dfrac{\ln{16}}{0.15}=t_1=4.67\approx 5\;h$

d) $t_2=?\; (N_0→3N_0 \Longrightarrow 250 → 3\cdot250 =750)$

$N(t)=250 e^{0.15t}\\ 750=250 e^{0.15t_2} \\ \ln{3} =\ln{e^{0.15t_2}}\\ t_2=\dfrac{\ln{3}}{0.15} = 2.99 \approx 3\;h$

6 0

3 years ago

What is the square root of 5?

shutvik [7]

5 x 5 = 25

answer: 25.

7 0

3 years ago

Read 2 more answers

Tom can paint a chair in 5 minutes. Together Tom and Sue can paint the chair in 4 minutes. How long does it take for Sue to pain

Angelina_Jolie [31]

2 minutes because if u take 4 for the amount of time it take sue and tom and divide it by 2 for two people painting than your quotient is going to be 2.

it takes sue Sue 2 minutes to paint a chair by herself.

3 0

3 years ago

The population of a small town in central Florida has shown a linear decline in the years 2001-2012. In 2001 the population was

earnstyle [38]

Answer:

Step-by-step explanation:

First of all, to keep our numbers manageable, we are going to let year 2001 = 0 so year 2012 = 11. The coordinates that result from these years/population numbers are (0, 22200) and (11, 13950). Since this linear, we can plug those 2 coordinate pairs into the slope equation to find the rate at which the population is decreasing in people per year:

$m=\frac{13950-22200}{11-0}=\frac{-8250}{11}=-750\frac{people}{year}$ That means that the town is losing people at the rate of 750 per year. We can use that slop along with one of the coordinate points to write the linear equation representing this situation: