Researchers recorded that a certain bacteria population declined from 450,000 to 900 in 30 hours at this rate of decay how many bacteria will there be in 13 hours

Answers

Answer 1

Answer:

30,455

Step-by-step explanation:

Exponential decay

y = a(1 - b)^x

y = final amount

a = initial amount

b = rate of decay

x = time

We are looking for the rate of decay, b.

900 = 450000(1 - b)^30

1 = 500(1 - b)^30

(1 - b)^30 = 0.002

1 - b = 0.002^(1/30)

1 - b = 0.81289

b = 0.1871

The equation for our case is

y = 450000(1 - 0.1871)^x

We are looking for the amount in 13 hours, so x = 13.

y = 450000(1 - 0.1871)^13

y = 30,455


Related Questions

Joy is preparing 20 liters of a 25% saline solution. She has only a 40% solution and a 10% solution in her lab. How many liters of the 40% solution and how many liters of the 10% solution should she mix to make the 25% solution?

Answers

Answer:

10 Liters of 40% solution

Step-by-step explanation:

Answer:

10 liters of the 40% solution, and 10 liters of the 10% solution

Step-by-step explanation:

Let us say that x = the liters of the 40% solution, and y = liters of the 10% solution in her lab. We know that Joy is preparing a solution containing a total 20 liters, so x + y = 20. We can respectively create the following system of equations,

x + y = 20,

0.40x + 0.10y = 0.25 ( 20 )

And now we have to solve this system of equations for x and y, the liters of the 40% solution and the liters of the 10% solution,

[tex]\begin{bmatrix}x+y=20\\ 0.4x+0.1y=0.25\left(20\right)\end{bmatrix}[/tex]  ( Substitute x as 20 - y )

[tex]0.4\left(20-y\right)+0.1y=0.25\cdot \:20\end{bmatrix}[/tex] ( Isolate y )

[tex]8-0.3y=5[/tex] ⇒ [tex]80-3y=50[/tex] ⇒ [tex]-3y=-30[/tex] ⇒ y = 10

[tex]x=20-10 = 10[/tex] ⇒ x = 10

Therefore, there are 10 liters of both the 40% and 10% solution.

Please answer this correctly without making mistakes

Answers

Answer:

2 13/15 miles

Step-by-step explanation:

Hey there!

Well first we need to find the distance between Lancaster and Hillsdale and Lancaster to Silvergrove.

9 + 7 13/15

= 16 13/15

LS is just 14 miles.

Now we can do,

16 13/15 - 14

= 2 13/15 miles

Hope this helps :)

I need help on this question

Answers

Answer:

Figure G.

Step-by-step explanation:

Let's check through the values and calculate the radius and area for all the circle.

For circle R

Diameter = 2 feet

Radius= 1 feet

Area= πr²

Area= 3.14*1

Area= 3.14 feet²

CircleS

Diameter= 4 feet

Radius= 2 feet

Area= πr²

Area= 3.14*2²

Area= 12.56 feet²

Circle T

Diameter= 8 feet

Radius= 4 feet

Area = π r²

area= 3.14*4²

Area=50.24 feet²

Circle U

Diameter= 12 feet

Radius= 6 feet

Area = π r²

area= 3.14*6²

Area=113.04 feet²

The values of the radius and Area all match the graph in figure G

Help!!!!!!! Thank you!!!!!!!

Answers

Answer:

D

Step-by-step explanation:

The ratio of yellow paint to blue paint is 4:3. We can make the largest amount of green paint by using all of the 20 quarts of yellow paint so we have to solve for x in 4:3 = 20:x, since 4 * 5 = 20, 3 * 5 = x so we use 15 qts of blue paint, therefore we will have 20 + 15 = 35 qts of green paint.

Answer:

D

Step-by-step explanation:

Suppose a vine maple grows in height linearly. Four weeks after it is planted it stands 10.67 inches, and after seven weeks it is 15.67 inches tall. Write an equation that models the growth, in inches, of the vine maple as a function of time, in weeks. 1. What is the slope of the function? 2. How tall was the tree when it was first planted? 3. Write the function 4. How tall will the vine maple be after 16 weeks?

Answers

Answer:

Height (z)= 4+(5/3)(z)

Where z is the number of weeks

1). Slope = 4

2). Height= 5.67 inches

3).Height (z)= 4+(5/3)(z)

4).Height= 30.67 inches

Step-by-step explanation:

At week four

10.67= x+4y

Week 7

15.67= x+7y

Solving both equation simultaneously

3y= 5

Y= 5/3

15.67= x+7y

15.67= x+7(5/3)

15.67-35/3= x

15.67-11.67= x

4= x

The modeled equation is

Height (z)= 4+5/3(z)

Where z is the number of weeks

Slope of the function as compared to y= mx+c is 4

The first week of it's plantation

Height (z)= 4+5/3(z)

Height (1)= 4+5/3(1)

Height= 5.67 inches

After 16 weeks

Height (z)= 4+(5/3)(z)

Height (16)= 4+(5/3)(16)

Height= 30.67 inches

Help someone please!!

Answers

Answer:

A. 5:4

Step-by-step explanation:

Since the question mentions twelfths of a pie, it is easier to say each pie has 12 pieces or 36 total pieces ordered from the 3 pies. Ty ate 5 and Rob ate 15 which is 3 times more than Ty. A total of 20 pieces have been eaten from the 36 you started with. Eaten = 20 and Remaining = 16. So the ratio is 20:16 which is simplified to 5:4.

the answer is A. 5:4

please help me to answer this question​

Answers

Where’s the question

Answer:

I can not see any questions

Solve for x: x/25 > 5

Answers

Answer:

x>125

Step-by-step explanation:

Answer:

x > 125

Step-by-step explanation:

Multiply each side by 25, so it now looks like this: x > 125

I hope this helps!


The population of Jacksonville is 836,507. What is the population rounded to the
nearest hundred thousand?
A. 900,000
O
B. 850,000
C. 840,000
o D. 800,000​

Answers

Answer:

D. 800,000

Step-by-step explanation:

It is D because you find the hundred thousand place which is the 8, the you go to the number next door which is 3, if the 3 is 5 or greater the 8 will become a 9 or if it is not then it will stay the same. And everything to the left stays the same, everything to the right turns into zeros.

The time, X minutes, taken by Tim to install a satellite dish is assumed to be a normal random variable with mean 127 and standard deviation 20. Determine the probability that Tim will takes less than 150 minutes to install a satellite dish.

Answers

Answer: 0.8749

Step-by-step explanation:

Given, The time, X minutes, taken by Tim to install a satellite dish is assumed to be a normal random variable with mean 127 and standard deviation 20.

Let x be the time taken by Tim to install a satellite dish.

Then, the probability that Tim will takes less than 150 minutes to install a satellite dish.

[tex]P(x<150)=P(\dfrac{x-\text{Mean}}{\text{Standard deviation}}<\dfrac{150-127}{20})\\\\=P(z<1.15)\ \ \ [z=\dfrac{x-\text{Mean}}{\text{Standard deviation}}]\\\\=0.8749\ [\text{By z-table}][/tex]

hence, the required probability is 0.8749.

“Type ‘equal, supplementary, complementary, or vertical in the space provided’”

Answers

Answer:

Supplementary

Step-by-step explanation:

When the sum of 2 angles equal 180°, they are called supplementary angles. And they also form a straight line together.

<AOB (40°) and <BOC (140°) are not equal angles.

<AOB (40°) and <BOC (140°) are not complementary angles. Complementary angles add up to equal 90°.

<AOB (40°) and <BOC (140°) are not vertical angles. Vertical angles are opposite angles formed when two lines intersect.

<AOB (40°) and <BOC (140°) are supplementary angles. They add up to equal 180°.

Help plz! Jim is climbing a mountain that has a base 150 feet above sea level. If he climbs 233 feet then descends into a cave 64 feet, how far above sea level is Jim

Answers

150+233-64=319
Jim is 319 ft above sea level.

Answer:

150+233-64=319

Jim is 319 ft above sea level.

Step-by-step explanation:

A middle school has 470 students. Regina surveys a random sample of 40 students and finds that 28 have cell phones. How many students at the school are likely to have cell phones? A. 132 students B. 188 students C. 329 students D. 338 students Please include ALL work! <3

Answers

Answer:

C. 329

Step-by-step explanation:

So 28 is 70% of 40

so we know that 70% percent of students have phones

70% of 470

329

Thats how I solved it have a great day :)

2 divided by ___=42 two divided by what equals 42?

Answers

2 divided by 0.048=42

In a mathematics class, half of the students scored 87 on an achievement test. With the exception of a few students who scored 52, the remaining students scored 71. Which of the following statements is true about the distribution of scores?

Answers

Answer:the mean is greater than the median

Step-by-step explanation:

The mean is less than the median. Then the correct option is A.

What are statistics?

Statistics is the study of collection, analysis, interpretation, and presentation of data or to discipline to collect, and summarise the data.

Half the students scored 87.  

The next highest score is 71.

Then the median will be

(71+ 87) / 2 = 79

A few students scored 52, so the mean is slightly lower than the mean of 71 and 87.

Thus, the mean is less than the median.

Then the correct option is A.

The missing options are given below.

A. The mean is less than the median.

B. The mean and the median is the same.

C. The mean is greater than the mode.

D. The mean is greater than the median.

More about the statistics link is given below.

https://brainly.com/question/10951564

#SPJ2

What is the missing statement in step 10 of the proof?

Answers

Answer:

c/sin C = b/sin C

Step-by-step explanation:

Look at the statement in the previous step and the reason in this step.

c sin B = b sin C

Divide both sides by sin B sin C:

(c sin B)/(sin B sin C) = (b sin C)/(sin B sin C)

c/sin C = b/sin B

Write a differential equation that fits the physical description. The at time t is proportional to the power of its .

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

The differential equation that fits the physical description is   [tex]\frac{d (v(t))}{dt} = z [v(t)]^2[/tex]

Step-by-step explanation:

 From the question we are told that

       The acceleration due to air resistance of a particle moving along a straight line at time t is proportional to the second power of its velocity v, this can be mathematically represented as

             [tex]a(t) \ \ \alpha \ \ \ [v(t)]^2[/tex]

Where  [tex]a(t)[/tex] is the acceleration at time t

and     [tex]v(t)[/tex] is the velocity at time  t

So  

=>         [tex]a(t)= z [v(t)]^2[/tex]

Where  z is a constant

Generally acceleration is mathematically represented as

       [tex]a(t) = \frac{d (v(t))}{dt}[/tex]

So

     [tex]\frac{d (v(t))}{dt} = z [v(t)]^2[/tex]

The data represents the daily rainfall​ (in inches) for one month. Construct a frequency distribution beginning with a lower class limit of and use a class width of . Does the frequency distribution appear to be roughly a normal​ distribution?

Answers

Answer:

The frequency distribution does not appear to be normal.

Step-by-step explanation:

The data provided is as follows:

S = {0.38 , 0 , 0.22 , 0.06 , 0 , 0 , 0.21 , 0 , 0.53 , 0.18 , 0 , 0 , 0.02 , 0 , 0 , 0.24 , 0 , 0 , 0.01 , 0 , 0 , 1.28 , 0.24 , 0 , 0.19 , 0.53 , 0 , 0, 0.24 , 0}

It is provided that the first lower class limit should be 0.00 and the class width should be 0.20.

The frequency distribution table is as follows:

Class Interval  Count

 0.00 - 0.19            21

 0.20 - 0.39             6

 0.40 - 0.59             2

 0.60 - 0.79             0

 0.80 - 0.99             0

  1.00 - 1 . 19             0

  1.20 - 1. 39             1

The frequency distribution does not appear to be normal. This is because the frequencies does not start and end at almost equivalent points and the mid-distribution does not consist of the highest frequency.

Thus, the frequency distribution does not appear to be normal.


Emily made a pot cream of pumpkin soup for thanksgiving dinner she put 5 cups of cream in the soup she poured the soup into 24 small bowl show much cream measured in oz is used for each small bowl of soup?

Answers

Answer:

each bowl can contain 5/3 oz. of soup.

Step-by-step explanation:

1 cup = 8 oz.

                  8 oz.

5 cups x --------------  =  40 oz.

                   1 cup

to get the measurement of each bowl,

40 oz. divided into 24 bowls.

therefore, each bowl can contain 5/3 oz. of soup.

Find the missing side of the triangle. A. √321 yd B. √221 yd C. 3√38 yd D. √21 yd

Answers

Answer:

(B) [tex]\sqrt{221}[/tex] yards

Step-by-step explanation:

Since this is a right triangle, we can use the Pythagorean Theorem to find the length of x.

The Pythagorean Theorem states that [tex]a^2 + b^2 = c^2[/tex], where a and b are our legs and c is the hypotenuse.

We need to find c, and we already know a and b, so let's substitute.

[tex]10^2 + 11^2 = c^2\\\\100+121=c^2\\\\221=c^2\\\\c=\sqrt{221}[/tex]

Hope this helped!

A die is rolled five times and the number of fours that come up is tallied. Find the probability of getting the given result. Exactly 3 fours.

A. 0.161

B. 0.002

C. 0.116

D. 0.216

Answers

Answer:

0.0321

Step-by-step explanation:

This can be found by binomial probability distribution as the  probability of success is constant. There are a given number of trials. the successive tosses are independent.

Here n= 5

The probability of getting a four in a roll of a die = 1/6

The probability of not getting a four in a roll of a die = 5/6

The probability of getting exactly three 4s in five throws is given by

5C3 (1/6)³ (5/6)² = 10 (0.0046) (0.694)= 0.0321

Mark each of the following as true or false and explain how you know.

Answers

true false false true...is the quick answer

Remember that negatives are always less than positive numbers.

If 2y = 6 - 3x, find y when x = 0

Answers

Answer:

2y= 6-3x when x=0

2y= 6-3(0)

2y= 6-0

2y= 6

y= 6/2

y= 3

#i'm indonesian

#hope it helps.

Answer:

[tex] \boxed{y = 3}[/tex]

Step-by-step explanation:

Given, x = 0

[tex] \mathsf{2y = 6 - 3x}[/tex]

plug the value of x

⇒[tex] \mathsf{2y = 6 - 3 \times 0}[/tex]

Multiply the numbers

⇒[tex] \mathsf{2y = 6 - 0}[/tex]

Calculate the difference

⇒[tex] \mathsf{2y = 6}[/tex]

Divide both sides of the equation by 2

⇒[tex] \mathsf{ \frac{2y}{2} = \frac{6}{2} }[/tex]

Calculate

⇒[tex] \mathsf{y = 3}[/tex]

Hope I helped!

Best regards!

Gavin goes to the market and buys one rectangle shaped board. The length of the board is 16 cm and width of board is 10 cm. If he wants to add a 2 cm wooden border around the board, what will be the area of the rectangle board?

Answers

Answer:

The answer is 216

Step-by-step explanation:

if there is a 2 cm border, that means that the sides will both become 2 centimeters longer. so (16+2)*(10*2) = 18*12 = 216.

A random sample of 1003 adult Americans was asked, "Do you think televisions are a necessity or a luxury you could do without?" Of the 1003 adults surveyed, 521 indicated that televisions are a luxury they could do without. Construct and interpret a 95% confidence interval for the population proportion of adult Americans who believe that televisions are a luxury they could do without out.

Answers

Answer:

The  95% confidence interval is  [tex]0.503 < p < 0.535[/tex]

The  interpretation is that there is 95% confidence that the true population proportion lie within the confidence interval

Step-by-step explanation:

From the question we are told that

    The  sample size is n  =  1003

     The number that indicated television are a luxury is  k  =  521

Generally the sample mean is mathematically represented as

           [tex]\r p = \frac{k}{n}[/tex]

          [tex]\r p = \frac{521}{1003}[/tex]

         [tex]\r p = 0.519[/tex]

Given the confidence level is  95% then the level of significance is mathematically evaluated as

       [tex]\alpha = 100 - 95[/tex]

       [tex]\alpha = 5\%[/tex]

       [tex]\alpha = 0.05[/tex]

Next we obtain the critical value of [tex]\frac{ \alpha }{2}[/tex] from the normal distribution table, the value is  

          [tex]Z_{\frac{\alpha }{2} } = 1.96[/tex]

The  margin of error is mathematically represented as

           [tex]E = Z_{\frac{\alpha }{2} } * \sqrt{ \frac{\r p (1- \r p )}{n} }[/tex]

=>       [tex]E = 1.96 * \sqrt{ \frac{ 0.519 (1- 0.519 )}{1003} }[/tex]

=>       [tex]E = 0.016[/tex]

The  95%  confidence interval is mathematically represented as

       [tex]\r p -E < p < \r p +E[/tex]

=>   [tex]0.519 - 0.016 < p < 0.519 + 0.016[/tex]

=>    [tex]0.503 < p < 0.535[/tex]

Can somebody please solve this problem for me!

Answers

Answer:

x = 200.674

Step-by-step explanation:

tan∅ = opposite/adjacent

Step 1: Find length of z

tan70° = 119/z

ztan70° = 119

z = 119/tan70°

z = 43.3125

Step 2: Find length z + x (denoted as y)

tan26° = 119/y

ytan26° = 119

y = 119/tan26°

y = 243.986

Step 3: Find x

y - z = x

243.986 - 43.3125 = x

x = 200.674

In a factory there are 100 units of a certain product, 5 of which are defective. We pick three units from the 100 units at random. What is the probability that none of them are defective

Answers

Answer:

Probability of picking all three non-defective units

= 7372/8085  (or 0.911812 to six decimals)

Step-by-step explanation:

Let

D = event that the picked unit is defective

N = event that the picked unit is not defective

Pick are without replacement.

We need to calculate P(NNN) using the multiplication rule,

P(NNN)

= 97/100 * 96/99 * 95/98

=7372/8085

= 0.97*0.969697*0.9693878

= 0.911812

The probability that none of the picked products are defective is;

P(None picked is defective) = 0.856

We are told that 5 are defective out of 100.

This means the number of good products that are not defective are 95.

Probability of the first picked product not being defective is written as; P(First picked not defective) = 95/100

Since the good ones have been picked, there will be 99 left of which the good ones are now 94. Thus, probability of second one not being defective = 94/99

Since two good ones have been picked, there will be 98 left and 93 good ones left. Thus, probability of third one not being defective = 93/98

Finally, Probability of none of the three being defective is;

95/100 × 94/99 × 93/98 = 0.856

Read more at; https://brainly.com/question/14661097

A man claims to have extrasensory perception (ESP). As a test, a fair coin is flipped10 times and the man is asked to predict the outcome in advance. He gets 7 out of10 correct. What is the probability that he would have done at least this well if hehad no ESP?

Answers

Answer:

I would say 70%

Step-by-step explanation:

He got 7 of of 10 (7/10 = 70%) right so I  would say he would do just as well without ESP since it doesn't exist.

Write a variable expression for a number w increased by 4 (A) 4 ÷ w (B) w + 5 (C) w + 4

Answers

Answer:

C) w+4

Step-by-step explanation:

w=the variable

+4= increased by 4

HOPE THIS HELPS!!!!!! :)

<33333333333

Which option is correct and how would one solve for it?

Answers

Answer:

-3/5, -1, -5/3,  -3, -7

Step-by-step explanation:

Let x go from 1 to 5

x =1      (1+2)/(1-6) = 3/-5 = -3/5

x =2      (2+2)/(2-6) = 4/-4 = -1

x =3      (3+2)/(3-6) = 5/-3 = -5/3

x =4      (4+2)/(4-6) = 6/-2 = -3

x =5      (5+2)/(5-6) = 7/-1 = -7

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