HELP ME PLEASE ANYONE FOR 20 POINTS

Answer:

18 minutes

Step-by-step explanation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is the time,

and T is the half life.

A = 140 when t = 10.  Solve for the half life:

140 = 700 (½)^(10 / T)

0.2 = ½^(10 / T)

log 0.2 = (10 / T) log 0.5

10 / T = 2.32

T = 4.31

When A = 40, t is:

40 = 700 (½)^(t / 4.31)

0.057 = ½^(t / 4.31)

log 0.057 = (t / 4.31) log 0.5

t / 4.31 = 4.13

t = 17.8

Rounded to the nearest whole number, it takes 18 minutes.

The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes.

In mathematics, an exponential function is a relationship of the type y = ax, where x is an independent variable that spans the entire real number line and is expressed as the exponent of a positive number.

The half-life decay formula is given as,

N(t) = N₀ [tex](1/2)^{(t / T)}[/tex]

Where T is half-life while t is the time taken.

N₀ is the initial amount,

As per the given,

N(t) = 140 when t = 10.

140 = 700 [tex](1/2)^{(t / T)}[/tex]

Take log both sides,

log 0.2 = (10 / T) log 0.5

10 / T = 2.32

T = 4.31 minutes

Put N(t) = 40

40 = 700[tex](1/2)^{(t / 4.31)}[/tex]

Take log both sides,

log 0.057 = (t / 4.31) log 0.5

t / 4.31 = 4.13

t = 17.8 ≈ 18 minutes

Hence "The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes".

For more about exponential function,

https://brainly.com/question/15352175

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Answer:

P= 2

Step-by-step explanation:

10/7p+13/8+15/2p=-909/56

Combine like terms

10/7p+15/2p=-909/56-13/8

20p+105p/14=-909-13*7/56

125/14p=-909-91/56

125/14p= -1000/56

125/14p*14/125= -1000/56*14/125

simplify

P= 8/4=2

And for #8 n =1 I answered this question it

Search

Answer:

Choice D

Step-by-step explanation:

3 ÷ 4/5

We need to have 3 of something and divide it into 4/5

This eliminates choices B and C because those have 4/5 of something

Choice A is giving away which is subtracting

Choice D is 3 lbs divide into 4/5 lb groups

Answer:

100,000

You take 1,000 because it's in the thousandths place of 1,255. The value of that one is 1,000 so you multiply that times 100, which is the value of 1 in 82,175.

Answer:

Step-by-step explanation:

Answer:

75

Step-by-step explanation:

Let x = total bill

x*63% = 47.25

x *.63 = 47.25

Divide each side by .63

x*.63/.63 = 47.25/.63

x=75

Answer:

3 1/4

Step-by-step explanation:

Hey there!

Well if Cedarburg to Westford is 8 3/4 miles and Oxford to Westford is 5 1/2 miles, we can make the following,

CO = CW - OW

CO = 8 3/4 - 5 1/2

Make the denominators the same,

5 1/2

improper

11/2

*2

22/4

Proper

5 2/4

8 3/4 - 5 2/4

3 1/4 miles

Hope this helps :)

Hi there! :)

Answer:

[tex]\huge\boxed{a < 5}[/tex]

Given:

7a + 13 < 48

Isolate the variable "a" by subtracting 13 from both sides:

7a - 13 < 48 - 13

7a < 35

Divide both sides by 7:

7a/7 < 35/7

a < 5.

Answer:

a < 5

Step-by-step explanation:

7a + 13 < 48

Subtract 13 from each side

7a + 13-13 < 48-13

7a < 35

Divide each side by 7

7a/7  < 35/7

a < 5

Answer:

3 years

Step-by-step explanation:

Use the formula I = prt, where I is the interest money made, p is the starting amount of money, r is the interest rate as a decimal, and t is the time the money was borrowed.

Plug in the values and solve for t:

108 = (1200)(0.03)(t)

108 = 36t

3 = t

= 3 years

Answer:

Step-by-step explanation:

1 dollar = 30 cents tax + 70 cents net income

The ratio of taxes to net income:

Correct choice is D

If 30cents are out then net income=100-30=70

ratio:-

[tex]\\ \rm\Rrightarrow \dfrac{30}{70}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{3}{7}[/tex]

[tex]\\ \rm\Rrightarrow 3:7[/tex]

9514 1404 393

Answer:

  12 units

Step-by-step explanation:

The ratio of the base to the other sides is ...

  4 : 7 : 7

The perimeter is a total of 4 +7 +7 = 18 ratio units, so each ratio units stands for 54/18 = 3 length units.

The base length is then ...

  (4 ratio units)(3 length units/ratio unit) = 12 length units

━━━━━━━☆☆━━━━━━━

▹ Answer

180 miles

▹ Step-by-Step Explanation

Distance = mph * hours

Distance = 45 mph * 4 hrs

Distance = 180 miles

Hope this helps!

CloutAnswers ❁

━━━━━━━☆☆━━━━━━━

Answer:

maybe it's 10.because c is 10,b is 10,and so as s.

hence s is 10 also.

Answer:

Solution : 5.244 - 16.140i

Step-by-step explanation:

If we want to express the two as a product, we would have the following expression.

[tex]-6\left[\cos \left(\frac{2\pi }{5}\right)+i\sin \left(\frac{2\pi }{5}\right)\right]\cdot 2\sqrt{2}\left[\cos \left(\frac{-\pi }{2}\right)+i\sin \left(\frac{-\pi \:}{2}\right)\right][/tex]

Now we have two trivial identities that we can apply here,

( 1 ) cos(- π / 2) = 0,

( 2 ) sin(- π / 2) = - 1

Substituting them,

= [tex]-6\cdot \:2\sqrt{2}\left(0-i\right)\left(\cos \left(\frac{2\pi }{5}\right)+i\sin \left(\frac{2\pi }{5}\right)\right)[/tex]

= [tex]-12\sqrt{2}\sin \left(\frac{2\pi }{5}\right)+12\sqrt{2}\cos \left(\frac{2\pi }{5}\right)i[/tex]

Again we have another two identities we can apply,

( 1 ) sin(x) = cos(π / 2 - x )

( 2 ) cos(x) = sin(π / 2 - x )

[tex]\sin \left(\frac{2\pi }{5}\right)=\cos \left(\frac{\pi }{2}-\frac{2\pi }{5}\right) = \frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}[/tex]

[tex]\cos \left(\frac{2\pi }{5}\right)=\sin \left(\frac{\pi }{2}-\frac{2\pi }{5}\right) = \frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}[/tex]

Substitute,

[tex]-12\sqrt{2}(\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}) + 12\sqrt{2}(\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4})[/tex]

= [tex]-6\sqrt{5+\sqrt{5}}+6\sqrt{3-\sqrt{5}} i[/tex]

= [tex]-16.13996 + 5.24419i[/tex]

= [tex]5.24419i - 16.13996[/tex]

As you can see option d is the correct answer. 5.24419 is rounded to 5.244, and 16.13996 is rounded to 16.14.

Answer:

James town is 5 meters higher than Takoradi​ .

Step-by-step explanation:

Given:

Height of James town = 2 meters below sea level

Height of Takoradi town = 7 meters below sea level

To find:

How much higher is James town that Takoradi = ?

Solution:

As we can see the standard of height is how much the town is below the sea level.

So, the height of town having lesser value will be at a higher level.

Value of Height of James town is lesser than that of Takoradi town.

Therefore, James town is at a higher level.

Difference of height = 7 meters - 2 meters = 5 meters

So, the answer is:

James town is 5 meters higher than Takoradi.

Step-by-step explanation:

Hello, there!!!!

It's simple lets get started with simple solution.....

Given,

AC= 7cm

BC= 25cm

let AB be x.

Now, As it is a Right angled triangle, taking angle B as a refrence angle. we get,

h= BC= 25cm

p= AC= 7cm

b= AB= x

now, by Pythagoras relation we get,

[tex]b = \sqrt{ {h}^{2} - {p}^{2} } [/tex]

[tex]or \: b = \sqrt{ {25}^{2} - {7}^{2} } [/tex]

By simplifying it we get,

b= 24cm

Therefore, the value of AB is 24 cm.

Hope it helps...

Answer:

7 quarts

Step-by-step explanation:

total paint = paint used + paint left

total paint = 2 +5

total paint 7

Answer:

Next three terms after 27 are 36, 45 and 54. I hope this will help .

Answer:

29 years of experience.

Step-by-step explanation:

So let's take the expression step by step.  Remember that you need to follow the order of precedence here for the operations.  Parentheses, exponentials, multiplication, and addition.

-5 + { 4 * 6 + 3 + 1 + [ 3 - ( 4 - 8 ) + ( 3 - 2 ) ] }

-5 + { 4 * 6 + 3 + 1 + [ 3 - ( -4 ) + ( 1 ) ] }

-5 + { 4 * 6 + 3 + 1 + [ 3 + 4 + 1 ] }

-5 + { 4 * 6 + 3 + 1 + [ 8 ] }

-5 + { 24 + 3 + 1 + 8 }

-5 + { 36 }

29

So the teacher has 29 years of experience.

Cheers.

Answer:

a) In the interval  (  55,9  ;   456,7 ) we will find 99,7 % of all values

b) In the interval  (  122,7  ;  389,9 ) we find 95,4 % of all values

Step-by-step explanation:

For a Normal distribution N (μ ; σ ) the Empirical rule establishes that the intervals:

( μ  ±  σ  )          contains 68,3 % of all values

( μ  ±  2σ  )        contains 95,4 % of all values

( μ  ±  3σ  )        contains 99,7 % of all values

If   N ( 256,3 ; 66,8 )

σ  =  66,8        ⇒   3*σ  = 3 * 66,8  = 200,4

Then:     256,3 - 200,4  =  55,9

And        256,3 + 200,4 = 456,7

a) In the interval  (  55,9  ;   456,7 ) we will find 99,7 % of all values

b) 2*σ  = 2 * 66,8  = 133,6

Then  256,3 - 133,6  = 122,7

And    256,3 + 133,6 = 389,90

Then in the interval  (  122,7  ;  389,9 ) we find 95,4 % of all values

A can do a piece of work in 10 days and B can do it 15 days. If both of them are working together, half of the work can be finished in?

Here we find,LCM of 10 and 15 is 30.

Working together, A and B can do

So, they would require 30/5 or 6 days to complete the task.

Answer:

B

Step-by-step explanation:

A conjugate is a term that has the same real part of its original but opposite terms of the second sign

Look at

[tex]3 + 6i[/tex]

The real part is 3 so B and C are the only possible answer.

The conjugate has the opposite sign of the second sign so the answer is

B

[tex]3 - 6i[/tex]

Answer:

-1

Step-by-step explanation:

Pick two points on the line

(0,2) and (2,0)

Using the slope formula

m = ( y2-y1)/(x2-x1)

    = ( 0-2)/(2-0)

    = -2/2

  = -1

Answer:

-1

Step-by-step explanation:

Use two points on the line to find the slope, using rise over run.

We can use the points (0, 2) and (2, 0).

From the first point to the other, the y value decreases by 2 and the x value increases by 2.

Use rise (change in y value) over run (change in x value):

-2 / 2

= -1

So, the slope is -1.

Answer:

Interval Level of Measurement

Step-by-step explanation:

The Interval level of measurement highlights the distances between two measurements. These distances are meaningful and could be rated as low intervals or high intervals. Intervals also indicate class and order between measurements. The inauguration of the United States President is an event that occurs 72 to 78 days after the presidential election. It is usually done as a private and public oath-taking ceremony on January 20, four years after the last presidential election. So, even if the president is on a second term, this event must be held.

The last U.S presidential election occurred on January 20, 2017, and the next one will be held on January 21, 2021. So there is an interval of four years between the last and next U.S presidential inauguration ceremony.

Answer:

D. 104

Step-by-step explanation:

[tex]y \: \alpha \: \frac{1}{ {x}^{2} } \\ \\ y = \frac{k}{ {x}^{2} } [/tex]

when y is 26, x is 4:

[tex]26 = \frac{k}{ {(4)}^{2} } \\ k = 416[/tex]

when x is 2:

[tex]y = \frac{416}{ {x}^{2} } \\ \\ y = \frac{416}{ {(2)}^{2} } \\ y = 104[/tex]

Answer:

D; 104

This is the correct answer

Answer:

[tex]42-j=16[/tex]

Step-by-step explanation:

"Decreased by" means subtraction.

The information says 42 decreased "by Jose's savings", which is represented by j.

"Is" means equal to.

Put it all together:

[tex]42-j=16[/tex]

:Done

Answer:

j - 42 = 16

Step-by-step explanation:

J = Jose Savings

42 = the amount decreased

16 = the left amount

J-42 = 16

j = 16+42

J = 58

Jose's savings was $58.

Hey there! I'm happy to help!

We see that y is equal to 3/2x-2. We can replace the y in the first equation with 3/2x-2 because they are equal and we can solve for x.

3x-2(3/2x-2)=-8

We use the distributive property to undo the parentheses.

3x-3x+4=-8

We combine like terms.

4=-8

We see that since there is no x anymore, there cannot be a solution. We have no x value to solve for the y value either, so there is no solution to this system of equations.

Have a wonderful day! :D

Answer:

D

Step-by-step explanation:

0.0015

hope this helps

Answer :

[tex] \frac{2 {x}^{3} + 7 {x}^{2} + 3x - 4}{ {x}^{3} + 3 {x}^{2} + x - 1} [/tex]

Step-by-step-explanation :

I did the explanation in the picture.