8. A substance has a half life of 2.347 minutes.
a. If the initial amount of the substance was 110.4 grams, how many half-lives will have passed
before the substance decays to 6.9 grams.
b. What is the total time of the decay?

Answers

Answer 1

Answer:

a.) 4 half lives have passed

b) 9.388 minutes

Step-by-step explanation:

Formula for exponential growth / decay is given as:

[tex]A=A_0b^{\frac{t}{c}}[/tex]

Where [tex]A[/tex] is the final population

[tex]A_0[/tex] is the initial population

[tex]b[/tex] is the growth factor

[tex]c[/tex] is the time taken for the growth 'b'

[tex]t[/tex] is the amount of time

Here, we are given that:

[tex]A[/tex] = 6. 9 grams

[tex]A_0[/tex] = 110.4 grams

[tex]b = \dfrac{1}{2}[/tex]

[tex]c = 2.347[/tex] min

To find:

a.) Number of half lives taken for the decay.

b.) Total time in the decay.

Solution:

a.) Number of half lives taken for the decay is nothing but equal to [tex]\frac{t}{c}[/tex].

Putting the values in the formula, we get:

[tex]6.9=110.4\times \frac{1}2^{\frac{t}{c}}\\\Rightarrow 6.9=110.4\times 0.5^{\frac{t}{c}}\\\Rightarrow 0.0625=0.5^{\frac{t}{c}}\\\Rightarrow \dfrac{t}{c} =4[/tex]

Therefore, the answer is:

4 half lives have passed.

b.) Total time of decay. We have to find the value of [tex]t[/tex] here.

From answer of part a.):

[tex]\dfrac{t}{c} =4\\\Rightarrow \dfrac{t}{2.347} =4\\\Rightarrow t =\bold{9.388\ min}[/tex]


Related Questions

^DEF and ^RSQ are shown in the diagram below

Based on the information provided in the diagram, what is mZQ in degrees?

Answers

Answer:

53.3 degrees

Step-by-step explanation:

∆DEF and ∆RSQ are similar. We know this, because the ratio of their corresponding sides are equal. That is:

DE corresponds to RS

EF corresponds to SQ

DF corresponds to RQ.

Also <D corresponds to <R, <E corresponds to <S, and <F corresponds to <Q.

The ratio of their corresponding sides = DE/RS = 6/3 = 2

EG/SQ = 8/4 = 2

DF/RQ = 4/2 = 2.

Since the ratio of their corresponding sides are equal, it means ∆DEF and ∆RSQ are similar.

Therefore, their corresponding angles would be equal.

Thus, m<Q = m<F

Let's find angle F

m<F = 180 - (98 + 28.7)

m<F = 53.3°

Since <F corresponds to <Q, therefore,

m<Q = 53.3°

I believe the answer is B can someone confirm

Answers

Answer:

Looks right, b is right

Step-by-step explanation:

The rest are false

Answer:

yes you are right

Step-by-step explanation:

B is correct

The quotient of 5 divided A is great than, less than or equal to the quotient of A divided 5?

Answers

Answer:

It will depend

Step-by-step explanation:

If a<5 then quotient of 5 divided A is greater than the quotient of A divided 5.

If a=5 then quotient of 5 divided A is equal to the quotient of A divided 5.

If a>5 then quotient of 5 divided A is less than the quotient of A divided 5.

In one year, a dog's weight increased from 64 to 80 pounds. By what percentege did the dog's weight increase?

Answers

Answer:

125%

Step-by-step explanation:

first set up a proportion where 80 is over 64 and x is over 100 . 80/64=x/100

then cross multiply and divide to get 125%

M



Can someone please help me!!

Answers

Answer:

64 is the measure of angle A.

Step-by-step explanation:

===================================================================

The triangle is an isosceles triangle, so when you use the supplementary theorem for angle BCA and 116, you get 64. And since the base pairs are equal, angle A is 64.

===================================================================

Answer:

m∠A = 64°

Step-by-step explanation:

If AB = BC , then ∠CAB ≅ ∠ACB

m∠ACB = 180° - 116° = 64° ⇒ m∠A = 64°

Ratios
Express each ratio as a fraction in the simplest for
MI
1) 18 pounds to 22 pounds

Answers

Answer:

h

Step-by-step explanation:

eteujj

18 : 22
18/22

They’re both divisible by 2

18/22 divided by 2/2

(18/22) / (2/2)= 9/11


So, the ratio as a fraction is simplest form would be

9/11

can you plz help me with this​

Answers

Answer:

Step-by-step explanation:

im traade =23423423423

Which point is NOT part of the solution set?


A. (-1, -3)

B. (5, 1)

C. (20, -5)

D. (0, 0)

Answers

Answer:

c becues its a bigger number

Step-by-step explanation:

Answer: A.  (-1, -3)

This point is on the boundary line, but the boundary line is a dashed line. So this point is not part of the solution. The dashed line is like an electric fence you can get closer to, but you cannot touch it. It's due to the fact there isn't any "or equal to" as part of the inequality sign. So that's why (-1,-3) is not in the solution set. If the boundary line was solid, then (-1,-3) would be a solution.

Points like (5,1), (20,-5) and (0,0) are solutions because they are in the pink shaded region, and they aren't on the boundary.

Answer this and ill will help back and give brainliest

Answers

Answer:

Gh 2

Step-by-step explanation:

2

A. f(x)=2x+1

B.f(x)=x/2-1

C. f(x)=2x-1

D.f(x)=x/2+1

Answers

Answer:

D

Step-by-step explanation:

If you use a calculator and try each you will see that d is correct 3/2+1=2.5 3 is your x from the table and keep doing that with all and see if its true which it is

I REALLY NEED THIS PLEASE ANSWER IT. ITS 50 POINTS.

Josh loves to sing and enters a karaoke contest. The singing order for the 21 contestants is randomly selected. What is the probability that Josh is not one of the first two singers?

Answers

Answer:

BANANA

Step-by-step

Answer:

2/21

Step-by-step explanation:

Brian bought 20 apples. He bought twice as many as Timmy. How many apples did Timmy buy?

Answers

Answer:

10 apples

Step-by-step explanation:

if Person a bought twice as many apples as person b then it would be ten considering 10 x 2 = 20

eqaution: 10 divided by 2

Find the equation of the line that is parallel to the given line and passes through the given point.

y = −4x + 7; (9, 5)

The equation is y =__________.

Answers

Answer:

y= 4 x  

Step-by-step explanation:

y =4x − 7

 

Choose a point that the parallel line will pass through.

(0 , 0 )

Use the slope-intercept form to find the slope.

Tap for fewer steps...

The slope-intercept form is  

y = m x+ b , where  m  is the slope and b  is the y-intercept. y = m x + b

Using the slope-intercept form, the slope is  

4 . m = 4

To find an equation that is parallel to  y = 4 x − 7 , the slopes must be equal. Using the slope of the equation, find the parallel line using the point-slope formula.

( 0 , 0 ) m = 4

Using the point-slope form  

y − y 1 = m ( x −x 1 ) , plug in  m = 4 ,  x 1 = 0 , and  y 1 = 0 .

y − ( 0 ) = ( 4 )( x − ( 0 ) )

Solve for  y.

Subtract  0  from  y .

y = ( 4 ) ( x − ( 0 ) )

Subtract  0  from  x .

y= 4 x  

HOPE THIS HELPS!

pLEASE MARK bRAINLIEST! :)

HELP PLEASE IM LOOSING MY MIND

Answers

Answer:

C is da answer

Step-by-step explanation:

Answer:

never seen such big horror

but I think it D using logic

in which pair of figures can figure A be taken to figure B by a rotation

Answers

Answer:

Pair 1

Step-by-step explanation:

if the shape A rotated 180 degrees it would reach shape B

If the shape A is rotated 180 degrees then it would reach shape B. so the correct option is Pair 1.

How does rotation by 90 degrees changes coordinates of a point if rotation is with respect to origin?

Let the point be having coordinates (x,y).

Case 1: If the point is in first quadrant:

Subcase: Clockwise rotation:

Then (x,y) → (y, -x)

Subcase: Counterclockwise rotation:

Then (x,y) → (-y, x)

For points on axes, WE can take that point in any of the two surrounding quadrants. Example, if the point is on positive x axis, then it can taken as of first quadrant or fourth quadrant.

On origin there is No effect as we assumed rotation is being with respect to origin.

Therefore, if the shape A is rotated 180 degrees then it would reach shape B.

Learn more about rotation of a point with respect to origin here:

https://brainly.com/question/18856342

#SPJ2

A laboratory scale is known to have a standard deviation of Ï = 0.001 gram in repeated weighings. Scale readings in repeated weighings are Normally distributed, with mean equal to the true weight of the specimen. A particular specimen is weighed 8 times on this scale. The average weight is x ¯ = 4.1602 grams. A 99% confidence interval for the true weight of the specimen is:_______

Answers

Answer:

the confidence interval for the true weight of the specimen is;

4.1593 ≤ μ ≤ 4.1611

Step-by-step explanation:

We are given;

Standard deviation; σ = 0.001

Sample size; n = 8

Average weight; x¯ = 4.1602

We are given a 99% confidence interval and the z-value at this interval is 2.576

Formula for confidence interval is;

CI = x¯ ± (zσ/√n)

Plugging in the relevant values, we have;

CI = 4.1602 ± (2.576 × 0.001/√8)

CI = 4.1602 ± 0.000911

CI = (4.1602 - 0.000911), (4.1602 + 0.000911)

CI ≈ (4.1593, 4.1611)

Thus, the confidence interval for the true weight will be expressed as;

4.1593 ≤ μ ≤ 4.1611

Where μ represents the true weight

Pls solve 30 points math

Answers

Answer:

(6,0)

Step-by-step explanation:

 

.
On a farm a worker takes 15 minutes to pack 162 eggs into 9 cartons. How many eaggs are in each carton?

Answers

Answer: 18 eggs in one carton

Step-by-step explanation:

Basically, the 15 minutes is irrelevant to solve this problem so don’t worry about it. All you have to do to solve this is doing 162/9 to get 18.

Determine weather the following is real or complex
i^6-122-7i^2

Answers

Answer:

Real

Step-by-step explanation:

i^6-122-7i^2

(i^2)^3-122-7i^2

(-1)^3-122-7×(-1)

-1-122+7

-123+7

-116

So the final answer is -116

Simplify the rational expression -9x/x-x^2


See image attatched below SOMEONE HELP ME ASAP

Answers

Answer:

-9/x-1

The top one.

help, please
thank you
i will brainlist

Answers

Answer:

The answer is √156

Step-by-step explanation:

I hope this helped and if it did I would appreciate it if you marked me Brainliest. Thank you and have a nice day!

Jacob ate 21 chips ahoy cookies in 1 hour and Bryant ate 25 chips ahoy cookies in the same time, at this rate, how mant whole cookies could Bryant eat in 80 minutes

Answers

Answer:
55 cookies in 80 mins
Step-by-step explanation:
1 hour has 60 mins
so 25/60=0.417
0.417/3=0.139
0.139x4=0.556
so he can eat 55 cookies in 80 mins

Dracula has 48 pieces of candy. He gave ⅓ of his candy to his friend and 25% of his candy to his cousin. How many pieces of candy does Dracula have left?

Answers

Answer:

Dracula will be left with 24 candies

Step-by-step explanation:

The given problem is of fractions and percentages.

Given that

Total pieces of candy = 48

Now as it is mentioned that Dracula gives 1/3 of his candies to his friend, wee have to find the one third of the total pieces of candies first.

[tex]one-third\ of\ candies = \frac{1}{3} * 48\\= 16[/tex]

Dracula will be left with:

[tex]Candies\ left = Total\ candies - one\ third\ of\ candies\\= 48-16 = 32[/tex]

Dracula will be left with 32 candies after giving one third to his friend.

Now he gives 25% of remaining to his cousin

So,

[tex]25\%\ of\ 32\\= \frac{25}{100}*32\\=8[/tex]

Dracula will be left with: 32-8 = 24 candies

Hence,

Dracula will be left with 24 candies

Solve for x. Geometry problem.

Answers

Answer:

12.33

Step-by-step explanation:

6x - 2 + 9x - 3 = 180° (linear pair)

6x + 9x - 2 - 3 = 180°

15x - 5 = 180°

15x = 180 + 5

15x = 185

x = 185/15

x = 12.33

hope this helps you!

If the radius of the circle is 7 cm, find its area, rounded to 2 decimal places.

Answers

Answer:

14 :)

Step-by-step explanation:

0.9, 0.09, 0.1, 0.07
In order from smallest to largest

Answers

Answer:

0.07,0.09,0.1,0.9

Step-by-step explanation:

In general terms, Ascending means smallest to largest, 0 to 9, and/or A to Z and Descending means largest to smallest, 9 to 0, and/or Z to A. Ascending order means the smallest or first or earliest in the order will appear at the top of the list: For numbers or amounts, the sort is smallest to largest.

Explain how you know that two lines are perpendicular. Explain how you know that two lines are
parallel. Explain how you know that two lines are neither parallel or perpendicular. Give an example of a pair
of parallel lines and a pair of perpendicular lines.

Answers

Answer: Perpendicular lines intersect at right angles to one another. Parallel lines are lines that will go on and on forever without ever intersecting.

Step-by-step explanation:

Find (fog)(x).
f(x) = 6x
g(x) = x + 3
Write your answer as a polynomial in simplest form.
(fog)(x) = ????

Answers

Answer:

[tex](fog)(x)=6x+18[/tex]

Step-by-step explanation:

We are given:

f(x)=6x

and g(x)=x+3

We need to find (fog)(x)

(fog)(x) =f(g(x)) i.e we will put value of g(x) into f(x) i.e

[tex](fog)(x)=f(g(x))\\f(g(x))=6(x+3)\\f(g(x))=6x+18[/tex]

So, [tex](fog)(x)=6x+18[/tex]

a drawer contains 8 blue socks and 8 black socks. it is dark and you cannot tell the difference between colors

Answers

Answer:

yes

Step-by-step explanation:

i will trun on the light and see what color the socks are

please write complete question

Need help. Find the ratio of the perimeters and the ratio of the areas

Answers

Answer: The ratio of the perimeters is 3:4, and the ratio of the areas is I don't know how to find the ratio of the areas please show me this formula next time.

Step-by-step explanation:

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