A 41 gram sample of a substance that's used to detect explosives has a k-value of 0.1392. Find the substance's half life, in days.

Answers

Answer 1

Answer:

The substance half-life is of 4.98 days.

Step-by-step explanation:

Equation for an amount of a decaying substance:

The equation for the amount of a substance that decay exponentially has the following format:

[tex]A(t) = A(0)e^{-kt}[/tex]

In which k is the decay rate, as a decimal.

k-value of 0.1392.

This means that:

[tex]A(t) = A(0)e^{-0.1392t}[/tex]

Find the substance's half life, in days.

This is t for which [tex]A(t) = 0.5A(0)[/tex]. So

[tex]A(t) = A(0)e^{-0.1392t}[/tex]

[tex]0.5A(0) = A(0)e^{-0.1392t}[/tex]

[tex]e^{-0.1392t} = 0.5[/tex]

[tex]\ln{e^{-0.1392t}} = \ln{0.5}[/tex]

[tex]-0.1392t = \ln{0.5}[/tex]

[tex]t = -\frac{\ln{0.5}}{0.1392}[/tex]

[tex]t = 4.98[/tex]

The substance half-life is of 4.98 days.


Related Questions

Tammy knits blanket and scarves. On the first day of a craft fair, she sells 2 blankets and 5 scarves for $104

Answers

Answer:

Cost of Blanket = 32

Step-by-step explanation:

Let the cost of a blanket be = b , cost of a scarf be = s. Blanket price x Blanket Quantity & Scarf Price x Scarf Quantity sum up to be total sales.

So, Day 1 : 2b + 5s = 104 (i)  , Day 2 : 3b + 4s = 128 (ii)

Solving equations : Multiplying (i) by 3 , & (ii) by 2 , we get

6b  +  15s    =   312 ,

(-)6b + (-)8s =  (-)256

By elimination method, 15s - 8s = 312 - 256 → 7s = 56 → s = 56 / 7 = 8 .

Putting s value in any equation i], 2b + 5 (8) = 104 → 2b + 40 = 104 → 2b = 104 - 40 = 64 → b = 64 / 2 = 32

At a particular school 10% of children travel by bus.If this represent 120 children how many children attend the school?

Answers

Answer:

Total number of students= 1,200

Step-by-step explanation:

Giving the following information:

Proportion of students= 10%

Number of students that travel by bus= 120

To calculate the number of students that attends school, we need to use the following formula:

Total number of students= Number of students that travel by bus / proportion of students

Total number of students= 120 / 0.1

Total number of students= 1,200

can someone help me solve this equation and explain

Answers

Answer:

C

Step-by-step explanation:

Plug in the numbers in each equation to see if it fits. C is the best option

Ben and Jerry both have 7 numbers in their data set. Ben's average of his data set is 9. If Jerry average is 2 more than Ben, what does Jerry's data points have to sum to be

Answers

Answer:

Jerry's data points have to sum to be 77.

Step-by-step explanation:

We are given that

Ben and Jerry both have total numbers in their data set=7

Average of Ben's data set=9

Average of Jerry's data set=9+2=11

We have to find the Sum of Jerry's data points.

We know that

Average of data=Sum of numbers/Total number of data points

Using the formula

Average of Jerry' data =Sum of numbers in data/7

11=Sum of numbers in data/7

Sum of numbers=[tex]11\times 7[/tex]

Sum of numbers=77

Hence, sum of Jerry' data points=77

In ΔBCD, the measure of ∠D=90°, CB = 53, BD = 45, and DC = 28. What ratio represents the sine of ∠B?

Answers

Answer: 28/53

Step-by-step explanation:

trust me bro

The ratio that represents the sine of ∠B is 15/17.

What are trigonometric identities?

Trigonometric identities are the functions that include trigonometric functions such as sine, cosine, tangents, secant, and, cot.

Since the triangle has a right angle, we can find the length of the unknown side using the trigonometric notations SOH CAH TOA where;

Sin Ф = opposite side/hypotenuses side

Cosine Ф = adjacent side/hypotenuses side

Tangent Ф = opposite side/adjacent side

With respect to ∠B given that  ∠D=90°,

BD is the adjacent side and CB  is the hypotenuse side, DC is the opposite side

Hence ,Sin B = 15/17

Learn more about trigonometric;

https://brainly.com/question/21286835

#SPJ2

Mr. Jones has a box that is a right rectangular prism, It has a height of 2 inches, a width of 3 inches, and a volume of 30 cubic inches. How many inches long is Mr. Jones' box? *

Answers

First you do the 2x3=6 then after that you do 6/30=5

Find the circumference for the circle. Use 3.14 for pi (10.5cm) round to the nearest hindered as needed.

Answers

Might not be correct but…. C=2

It's 346.19 (rounded up)

Step-by-step explanation:

it can be simplified to: 3.14×(10.5x10.5)

Then just work down

3.14×110.25

346.185

and then round up bc of the 5

346.19

Which is true given the linear equation below?
3x+4y=4

Answers

Answer:

y= −3/4x + 1

x= -4/3y + 4/3

Step-by-step explanation:

Let's solve for y.

3x+4y=4

Step 1: Add -3x to both sides.

3x+4y+−3x=4+−3x

4y=−3x+4

Step 2: Divide both sides by 4.

4y4=−3x+44

y=−34x+1

___________

Let's solve for x.

3x+4y=4

Step 1: Add -4y to both sides.

3x+4y+−4y=4+−4y

3x=−4y+4

Step 2: Divide both sides by 3.

3x3=−4y+43

x= -4/3y + 4/3

math papa algebra caculator, thank me later

17. A can in the shape of a cylinder has a diameter of 6 centimeters and a height of 10 centimeters. Which measurement is closest to the total surface area of the can in square centimeters?​

Answers

Answer:

28.27

Step-by-step explanation:

Formula to find the total surface area is

2pi · r · h + 2pi r^2

the radius is 3cm

2pi · 3 · 10 + 2pi · 3^2

Cubes having side lengths of 3/4 in. are used to fill the right rectangular prism shown.

Answers

Answer:

I also want this question ans but u also

Answer:

36

Step-by-step explanation:

on the 4 [tex]\frac{1}{2}[/tex] in side you can fit 6 cubes

on the 1 [tex]\frac{1}{2}[/tex] in side you can fit 2 cubes

on the 2 [tex]\frac{1}{4}[/tex] in side you can fit 3 cubes

6 x 2 x 3 = 36

the answer is 36

The interior angle measure of a regular polygon is calculated with the following formula, where n represents the number of sides or interior angles of the regular polygon.




Determine the measure of the interior angles of a regular octagon and identify whether or not a regular octagon can be used as the only shape in a regular tessellation.


144°, no

135°, yes

144°, yes

135°, no



THE RIGHT ANSWER IS A 144°, no

Answers

Answer:

Step-by-step explanation:

The interior angle measure of a regular polygon is calculated with 180*(n-2)/n, where n represents the number of sides.

A regular octagon has 10 sides so it interior angle = 180*(10-2)/10

= 144

A tessellation is a tile pattern with the same polygon repeating. The polygon's interior angles must combine to form 360 degree. A regular octagon has interior angle of 144 degree which does not add to 360 degree. So a regular octagon cannot be used as the only shape in a regular tessellation.

The answer is 144°, no.

Answer:

Step-by-step explanation:

oct means 10

(n-2)/n * 180

= (10-2)/10 * 180

= 144°

144 + 144 = 288 < 360

144 + 144 + 144 = 432 > 360

so a regular octagon can NOT be used as the only shape in a regular tessellation.

ans is A

Tom has some marbles in two bags. In one bag he has 3 yellow, 2 green and 1 red marble. In the other bag he has 3 yellow, 3 green and 3 red marbles. If Tom takes one marble out of each bag, how probable is it that neither one is yellow?

Answers

Answer:

1 /3

Step-by-step explanation:

Bag 1 :

Yellow = 3 ; green = 2 ; red = 1

Total = 6

P(not yellow) = (2 +1) / 6 = 3/6 = 1/2

Bag 2 :

Yellow = 3 ; green = 3 ; red = 3

Total = 9

P(not yellow) = (2 +3) / 9 = 6/9 = 2/3

P(neither yellow from the two bags) = 1/2 * 2/3 = 2 /6 = 1/3

I’m just trynna get to 90% on this test before sunrise

Answers

Answer:

they are congruent

Step-by-step explanation:

Find the value for the given variables. Give the variables in simplest radical form. (square root form)

Answers

Answer:

Step-by-step explanation:

for y

take 60 degree as reference angle

using sin rule

sin 60=opposite /hypotenuse

[tex]\sqrt{3}[/tex]/2=11

22[tex]\sqrt{3}[/tex]/

22=y

for x

take 60 degree as reference angle

using cos rule

cos 60=adjacent/hypotenuse

1/2=x/11[tex]\sqrt{3}[/tex]

2x=11[tex]\sqrt{3}[/tex]

x=11[tex]\sqrt{3}[/tex]/2

x=9.52

x=10

A sector with an area of 30pi cm^2 has a radius of 10 cmWhat is the central angle measure of the sector in degrees?

Answers

Ikjyhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Lin charges $5.50 per hour to babysit. The amount of money earned, in dollars, is a function of the number of hours that she babysits.

Which of the following inputs is impossible for this function?
A:
-1
B:
2
C:
5
D:
8

Answers

-1 would be impossible.Since we are using the format of time there is no possible way to have a negative value

What are the following algebraic equations? You need to post those if you want the answer.

helppppppp please (3)

Answers

Answer:

please provide an image so we know what to solve

THERE ISNT ANYTHING HERE BRSTIE

Please help me out with this problem :)

Find the maximum value of P= x + 6y subject to the following constraints

Answers

Answer:

I cant tell what the answer is cause X and Y dont have a value

Step-by-step explanation:

Answer:

p=9

Step-by-step explanation:

40% of 36
can somone tell me what it is or how to do it because i am struggling

Answers

Answer:

14.4

Step-by-step explanation:

To find 40 percent of 36, here's how I do it. Just divide 36 by one hundred (move the decimal point two times to the left), giving you 0.36. Then multiply that by 40, and you get 14.4! Of course, there are multiple ways to do it, but that's just mine. If it doesn't work for you, try and search some formulas.

Answer:

Step-by-step explanation:

40/100*36

40*36/100

1440/100

14.4

so here if u divide 40% by 100 the % sign will automarically removed and here 40% 0f 36 means 40 and to remove % sign divide it by 100 and multply it by 36

Which number, best describes
withdrawing $100 from a
checking account?
A:
100
B.
- 100
C. +100
D.
| 100 |

Answers

Answer:

B

Step-by-step explanation:

It would be -100 because you would be withdrawing, not adding the amount, or staying with the same amount.

Answer:

B) -100

Step-by-step explanation:

Withdrawing means taking out, and subtracting is taking out a number, so the answer is B.


Please help me find the median to this table

Answers

hope this helps! feel free to clarify

Question 14
What is the absolute value of -8?
A. -8
B. O
C. 8
D. 16

Help plz

Answers

Answer:

C.8

| -8 | = 8

Explanation:

To find the absolute value of something, just find the complete opposite of a number. For example 25's absolute value is -25.

Hope this helps :)

Jack bought 50 lbs of clay for his art projects. He used 13.2 lbs to make a sculpture, and 0.72 lbs for each mug. How many mugs did Jack make if he had 28.88 lbs of clay left over?​

Answers

The answer would be 11 mugs
Explanation:50lbs-13.2 =36.8 and then 36.8-28.88=7.92 and finally you subtract so 7.92-0.72=11 and there’s your answer

123
30°
у
Find the values of x and y. Write your answers in simplest form.
x =
y=

Answers

Answer:

[tex]y=6\sqrt{3}[/tex]

[tex]x=18[/tex]

Step-by-step explanation:

[tex]Sin30=\frac{9}{12\sqrt{3} }[/tex]

[tex]1/2=y/12\sqrt{3}[/tex]

[tex]y=6\sqrt{3}[/tex]

[tex]tan30=y/x[/tex]

[tex]x=y/tan30=x=\frac{6\sqrt{3} }{1/\sqrt{3} }[/tex]

[tex]x=18[/tex]

------------------------

hope it helps...

have a great day!

Find the sum of the first 30 terms for the given arithmetic sequence.
8, 1, -6, -13, ...

Answers

sum= 2685
I hoped this helped!!

HELP! Vince weighs 160 pounds, and his friend Nadir weighs 140 pounds. Nadir calculated that his weight on another planet would be about 56 lb. Approximately what would Vince weigh on the other planet?

Answers

160/140 = x/56
cross multiply
(140)(x) = (160)(56)
140x = 8960
x = 8960/140
x = 64 lbs <== Vince's weight on the other planet

Answer:

64

Step-by-step explanation:

140/56=2.5

160/2.5=64

The average age of three people running for election is 42. A fourth person joins the race and the average drops to 40. What is the fourth
person's age?
OA. 32
OB. 34
ОО
C. 35
D. 36
E. 40

Answers

Answer:

B. 34

[tex]let \: sum \: of \: ages \: of\: 3 \: people \: be \: x \\ 42 = \frac{x}{3} \\ x = 126 \\ let \:age \: of \: fourth \: person \: be \: y \\ 40 = \frac{x + y}{4} \\ 160 = x + y \\ 160 = 126 + y \\ y = 34 \\ = 34 \: years[/tex]

5 (3z-3) =30 it’s from delta math 8 grade

Answers

Answer:

[tex]5[/tex]

Step-by-step explanation:

Substitute the value of the variable into the equation and simplify.

5 (3z-3) = 30

15 z - 15 = 30

15 z = 30+ 15

15z = 45

z= 45/ 15

z= 3

What is the area of a sector of a circle with a radius of 6, and an arc measure of 160 degrees?

A. 8π/3
B. 16π/3
C. 16 π

Answers

Answer:

16 pi

Step-by-step explanation:

First find the area of the circle

A = pi r^2

A = pi (6)^2

A = 36 pi

Then find the fraction of the circle the sector is

A circle is 360 degrees

160/360 = 4/9

Multiply the area by the fraction

4/9 * 36 pi

16 pi

Answer:

C: 16π

Step-by-step explanation:

Area of a sector =

[tex] = \frac{angle }{360} \times \pi \: r {}^{2} [/tex]

''A florist measures the lengths of roses. The lengths in inches of a dozen roses are given below'' I'm really confused.

Answers

Complete data:

13.5 13.5 13.25 13.0 13.25 13.5 13.0 13.25 13.0 13.25 12.75 12.75 Part A How many dots should go above each data value in the line plot? Type a number in each box

Answer:

12.75 ___ 2 dots

13.0 ____ 3 dots

13.25 ___ 4 dots

13.5 ___ 3 dots

Step-by-step explanation:

Given the data :

13.5 13.5 13.25 13.0 13.25 13.5 13.0 13.25 13.0 13.25 12.75 12.75

To know the Number of dots for each data value, we obtain the frequency of each data value ;

Length of Rose____ Frequency

12.75 _________:__ 2

13.0 ____________ 3

13.25 ___________ 4

13.5 ____________ 3

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