Element X decays radioactively with a half life of 11 minutes. If there are 870 grams
of Element X, how long, to the nearest tenth of a minute, would it take the element to
decay to 154 grams?
y = a(.5) t/h​

Answers

Answer 1

Answer:

27.5 minutes

Step-by-step explanation:

Using,

R/R' = 2ᵃ/ᵇ------------------ Equation 1

From the equation,

R = mass of Element X before radioactive decay, R' = mass of element X after radioactive decay, a = Time taken, b = half life.

Given: R = 870 grams, R' = 154 grams, b = 11 minutes.

Substitute these values into equation 1

870/154 = 2ᵃ/¹¹

(870/154)¹¹ = 2ᵃ

Solve for a

2ᵃ = (5.649)¹¹

2ᵃ = 187061.26

Taking the logarithm of both side,

Log2ᵃ = Log(187061.26)

⇒ a = log(187061.26)/log2

a = 8.272/0.301

a = 27.5 minutes


Related Questions

There’s 10 in total I need help with

Answers

Answer:

8√2

Step-by-step explanation:

this one is a right triangle so both side are equal since the angle is 45 degrees

If you stacked the cubes on top of each other to make an enormous tower, how high would they reach?

Answers

Answer:

Is this an actual question

8 x 10 inch rectangle.Total area is 168 in^2. Calculate the width of the rectangle. Which of the following quadratic equations would be used when solving this?

A - 2x^2 + 18x = 88
B - 4x^2 + 36x = 88
C - 4x^2 + 18x = 88
D - 2x^2 + 36 = 88

Answers

The answer will be c

Which of the following inequalities has the graphed solution below?
zzGroup of answer choices

x − 1 ≥ 0

x − 1 ≤ 0

x + 1 ≥ 0

x + 1 ≤ 0

Answers

I think either x + 1 >_0 or x - 1 >_0, but I personally would choose x + 1 >_0

Write a similarity statement comparing the three triangles in the diagram
P R S Q

Answers

Answer:

The answer is ΔJMK ≈ ΔMLK ≈ ΔJLM ⇒ answer (A)

Step-by-step explanation:

* Lets start with the equal angles i the three triangles

- In ΔJMK

∵ m∠JKM = 90°

∴ m∠KJM + m∠KMJ = 90 ⇒ (1)

- IN ΔMLK

∵ m∠MKL = 90°

∴ m∠KML + m∠KLM = 90° ⇒ (2)

∵ m∠KMJ + m∠KML = 90° ⇒ (3)

- From (1) , (2) , (3)

∴ m∠KJM = m∠KML

∴ m∠KMJ = m∠KLM

* Now lets check the condition of similarity in the 3 triangles

- At first ΔJMK and ΔMLK

- In triangles JMK , MLK

∵ m∠KJM = m∠KML

∵ m∠KMJ = m∠KLM

∵ m∠JKM = m∠MKL

∴ ΔJMK ≈ ΔMLK ⇒ (4)

- At second ΔJMK and ΔJLM

∵ m∠KJM = m∠MJL

∵ m∠KMJ = m∠MLJ

∵ m∠JKM = m∠JML

∴ ΔJMK ≈ ΔJLM ⇒ (5)

* If two triangles are similar to one triangle, then they are

similar to each other

- From (4) and(5)

∴ ΔJMK ≈ ΔMLK ≈ ΔJLM

hurry!!!! I need help ​

Answers

50 honestly have no clue sorry
X=50°
Because A and B side angles equal.
So x+17°=67°
So when you find the x from the problem
x=67°-17°=50°

pls help .. i will mark brainliest !

Answers

Answer:

Option 2, d; corresponding

Step-by-step explanation:

since 6 and 18 are on the same line (line d) and is on the same spot, they are considerd corresponding.

*
2) Does the following table show a function?

Answers

Answer:

no it does not show a fucntion

No now help me with my history work

Please help me solve these two questions

Answers

I hope the answer is helpful

i’m sorry this isn’t an answer i just rly need points so i can ask a test question

What is equity? What does it mean to have positive equity? What does it mean to have negative equity?

Answers

Equity, typically referred to as shareholders' equity (or owners' equity for privately held companies), represents the amount of money that would be returned to a company’s shareholders if all of the assets were liquidated and all of the company's debt was paid off in the case of liquidation. In the case of acquisition, it is the value of company sale minus any liabilities owed by the company not transferred with the sale.


Positive equity relates to assets you own that are financed by loans. The term positive equity is most commonly used with real estate investments, but there are other asset types where positive or negative equity is a consideration. As part of your financial situation, positive equity is a component of your overall net worth.



The concept of negative equity arises when the value of an asset (which was financed using debt) falls below the amount of the loan/mortgage that is owed to the bank in exchange for the asset. It normally occurs when the value of the asset depreciates rapidly over the period of use, resulting in negative equity for the borrower.

Which expression is equivalent to -6(-2\3 +2x)

-4-12x
-4+2x
4-12x
4+12x

Answers

Answer:

4 - 12x

Step-by-step explanation:

Use the distributive property.

-6(-2/3 +2x) =

= -6 × -2/3 + (-6) × 2x

= 4 - 12x

Work out the circumference of this circle.
Take a to be 3.142 and write down all the digits given by your calculator.
16.8 cm

Answers

Answer: 52.7856cm

Step-by-step explanation:

Circumference of a circle = 2πr

Note that radius = Diameter / 2 = 16.8/2 = 8.4cm

Circumference = 2πr

= 2 × 3.142 × 8.4

= 52.7856cm

Therefore, the circumference of the circle is 52.7856cm

СК - висота трикутника АВС. Знайдіть градусну міру кута А

Answers

Inglis please. Thank you.

You call 5 friends, tomorrow they call 5 each. Write an equation.

Answers

Answer:

5+5=10

Step-by-step explanation:

5+5=10

hope this helps. plz mark me as brainliest.

14. The diagonals of square ABCD intersect at E. If AE = 2, find the perimeter of ABCD.

Answers

Answer:

B, [tex]8\sqrt{2}[/tex]

Step-by-step explanation:

Diagonals of a square are congruent so AC= 4

using pythagorean theorem we can then do [tex]x^{2} +x^{2}[/tex]=[tex]4^{2}[/tex]

[tex]2x^{2} = 16\\x^{2} =8\\x=\sqrt{8} \\x=2\sqrt{2}[/tex]

Then for perimeter we times the [tex]2\sqrt{2}[/tex] by 4 and get

[tex]8\sqrt{2}[/tex]

Hope this helps and please mark brainliest!!

Determine the projection of u=1.6i+3.3j in the v=-2.1-.5j direction.

A.8i+.2j

B.2.3i+.5j

C. -.6i-1.3j

D. -1.2i-1.1j

Answers

Answer:

[tex]0.80i +0.2j[/tex]

Step-by-step explanation:

The projection of u on v is expressed as;

[tex]proj_{v} u = \dfrac{u*v}{|v|^2} * v[/tex]

Given

u=1.6i+3.3j

v=-2.1i-.5j

u*v = (1.6i+3.3j )*(-2.1i-0.5j )

u*v = 1.6i(-2.1i) + 3.3j(-0.5j)

u*v = -3.36 - 1.65

u*v = -5.01

|v|² = (√(-2.1)²+(-0.5)²)²

|v|² = (-2.1)²+(-0.5)²

|v|² = 4.41+0.25

|v|² = 4.66

Substitute into the formula;

[tex]= \frac{1.71}{-5.01} * (-2.1i - 0.5j)\\= -0.3413 (-2.1i - 0.5j)\\= 0.8i + 0.17j\\= 0.80i +0.2j[/tex]

Solve the following system of equations using addiction

Answers

Answer:

3x+y=13

+2x-y=12

SOlve it like what you would normally do

3x+2x=5x

y+(-y)=0

13+12=25

Basically

5x+0=25

Bring down all appropiate signs

Now solve that

5x=25

x=5

Now to find “y”

Plug in The “x”

3*5=15

15+y=13 now solve that and you’d get -2

If you plug it into the other one, it would be the same thing

2*5=10

10-y=12

-y=2

y= -2

x=5

y= -2

2. Write the equation of a circle that has a diameter of 12 units if its center is at (4,7).
O (x – 4)2 + (y – 7)2 = 144
O (x +4)2 + (y + 7)2 = 144
O (x – 4)2 + (y-7)2 = 36
O (x+4)2 + (y + 7)2 = 36

Answers

Answer:

The Answer is B

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius

Here diameter = 12, thus radius = 12 ÷ 2 = 6 and (h, k) = (2.5, - 3.5), thus

(x - 2.5)² + (y - (- 3.5))² = 6², that is

(x - 2.5)² + (y + 3.5)² = 36 ← equation of circle

Solve for X: x/5 - 7 = 2
Please give the correct answer. Thank You!

Answers

Answer:

x = 45

Step-by-step explanation:

[tex]\frac{x}{5} -7=2\\\\\frac{x}{5}=9\\\\x=45[/tex]

What is equivalent to 8?
A:2^3
B:3^-2
C:2^-3
D:3^2

Answers

2^3 is equivalent to 8.

Answer:   A:2^3

Step-by-step explanation:

8=2*2*2=(2)^3

A woman bought bars
of truck soap for #200. If
a bar is #2.50 more expensive.
She could have bought 2 less.
how many bars did she buy?​

Answers

Answer:

80

Step-by-step explanation:

200/2.50=80

pls help and show work i am so screwed if i don’t do well on this

Answers

Answer:

see in the picture mark brainliest if correct

Find the number of subsets in the set (x l x is a day of the week)
a. 124
b. 256
c. 127
d. 128

Answers

C hope that helps have a good one

12/5 divided by 21/10

Answers

exact form is 8/7 , as a decimal its 1.142 and mixed number form its 1 1/7

4.

Find the area of the shaded region.


A. 5x2 + 16x – 21

B. 7x2 + 28x + 27

C. 5x2 + 28x + 27

D. 5x2 + 28x + 21

Answers

Answer:

yay

Step-by-step explanation:

yayyayyayyayyayyyayyayayayyayaya

Answer:

D. 5x2 + 28x + 21

Step-by-step explanation:

First you want to find the area of the white rectangle

Then find the area of the beings rectangle

Then subtract beings minus white.

                                     Sorry it’s +21. The first answer in your list

                                      then thats correct

...............................................................................................................................................

5x^2+28x+21 confirmed from Cortez himself

Rearrange t= 5s + 4 to make s the subject.

Answers

The answer is 5s= t - 4.

PLEASE HELP!!!!!

Taylor's computer randomly generate numbers
between 0 and 4, as represented by the given uniform
density curve.
What percentage of numbers randomly generated by
Taylor's computer are between 1.5 and 3.25?
O 0%
1.75%
Random Number Generated
by Computer
25%
O 43.75%
1
2
3
Random Number

Answers

Answer: D

Step-by-step explanation:

just got it correct.

what do you think???​

Answers

Answer:

To entertain

Step-by-step explanation:

Because the dad made a joke to entertain, and the story is entertaining the readers.

Answer: entertain

Step-by-step explanation:

HELPPP ME PLSSS AND NO BOTS BC I WILL REPORT AND I BARELY HAVE POINT SO PLS HELP ME

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Answer: 52 1/2 inches. Draw a vertical line up from the 20 week marker and where that line intersects the slanted red line and. Then take a straight edge and draw a line parallel to the "week" line on the bottom of the graph from the intersection to intersect the height line. Where the second line crosses the height line that number is the height of the plant at 20 weeks.

plz help me please please​

Answers

Answer:

5%

Step-by-step explanation:

Answer:

5% increase

Step-by-step explanation:

30/600 equals .05 or 5%

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