Element X decays radioactively with a half life of 9 minutes. If there are 610grams of
Element X, how long, to the nearest tenth of a minute, would it take the element to
decay to 124 grams?
y = a(.5) t/h

Answers

Answer 1

A half-life of 9 minutes corresponds to a decay factor k such that

[tex]\dfrac12=e^{9k}\implies k=-\dfrac19\ln\left(\dfrac12\right)[/tex]

Then the time it takes for the substance to decay from 610 g to 124 g is time t such that

[tex]124\,\mathrm g=(610\,\mathrm g)e^{kt}[/tex]

Solve for t :

[tex]\dfrac{62}{305}=e^{kt}[/tex]

[tex]\ln\left(\dfrac{62}{305}\right)=kt[/tex]

[tex]t=\dfrac1k\ln\left(\dfrac{62}{305}\right)\approx20.686[/tex]

so it takes about 20.7 min for the 610 g sample to decay down to 124 g.


Related Questions

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If f(x) = -3x + 4, find f(-4)

Answers

Answer:

Step-by-step explanation:

-3x+4

-3(-4)+4

12+4

16

Answer:

3x+4

3(-4)+4

12+4

16

Step-by-step explanation:

A sequence of steps for solving the equation 3(x - 2) = 4 is shown. Match a property to each blank box to show the reason for each step. Question 6 options: 3(x - 2) = 4 3x - 6 = 4 3x = 10 x = 103 1. Given 2. Distributive Property 3. Addition property of equality 4. Division property of equality

Answers

Step-by-step explanation:

Given the equation;

3(x-2) = 4

A sequence of steps for solving the equation is as shown;

Step 1: Open the parenthesis by applying distributive law to distribute 3 over x and 2 as shown;

3(x-2) = 4

3(x)- 3(2) = 4

3x - 6 = 4

Step 2: Add 6 to both sides of the equation (Addition property)

3x-6+6 = 4+6

3x = 10

Step 3: Division property of equality. Divide both sides by 3;

3x = 10

3x/3 = 10/3

x = 10/3

Kelly currently has a checking account balance of $172.14. She makes a deposit of $27.45, and then spends $17.89 on dinner. How much money does she have now? *

Answers

Answer:

126.8 Hope this helps

2+4 i need help right now​

Answers

Answer:

6?

Step-by-step explanation:

Answer:

6

Step-by-step explanation:

2 + 4 =6

just add 2 by 4 than ans 6

A tree is 72 feet (ft) tall. How many inches (in) is this? First fill in the blank on the left side of the equation using one of the ratios. Then write your answer on the right side of the equation.

Answers

1 foot = 12 inches:

1/72 = 12/x

Cross multiply:

1x = 72 * 12

x = 864 inches

Give the values of the coefficients [a], [b], and [c], regarding the product in the form of ax^2-bx + xy - cy. Use "0" if the term isn't present.

Answers

Answer:

[tex]x^{2} -6x+xy-6y[/tex]

Step-by-step explanation:

Answer:

The values of coefficients a, b and c are

a=1

b=6

c=6

Step-by-step explanation:

We need to give the values of coefficients [a],[b] and [c]  regarding the product in the form of [tex]ax^2-bx + xy - cy[/tex]

The term given is: [tex](x+y)(x-6)[/tex]

First we will multiply the terms

[tex](x+y)(x-6)\\=x(x-6)+y(x-6)\\=x^2-6x+yx-6y[/tex]

Now comparing the product [tex]x^2-6x+yx-6y[/tex]  with the given form [tex]ax^2-bx + xy - cy[/tex]

The values of coefficients a, b and c are

a=1

b=6

c=6

PLZ Help Urgent. 15 POINTS, BRAINLY Guaranteed.
Plz Answer honestly or you will be reported.

Evaluate.

(2/7)^3

A: 8/343
B: 8/7
C: 3/343
D: 6/7

Answers

Answer:

8/343

so A

Step-by-step explanation:

#12: Kara is deciding between The Lyme Point Inn and Ever After Farms for 1 point

her wedding reception. The Lyme Point Inn charges $3,000 for the venue

and $100 for each meal. Ever After Farm charges $5,400 for the venue and

$70 for each meal. Write and solve an equation to find the number of

meals at which the total cost charged by the two venues would be the

same. *

Your answer

ooo

Answers

Answer:

80 meals

Step-by-step explanation:

Set up an equation where x is the number of meals:

100x + 3000 = 70x + 5400

Solve for x:

100x + 3000 = 70x + 5400

30x + 3000 = 5400

30x = 2400

x = 80

So, at 80 meals, the cost of the 2 venues will be the same

Answer:

80 metals

Step-by-step explanation:

100x + 3000 = 70x + 5400

How to Solve for x:

100x + 3000 = 70x + 5400

30x + 3000 = 5400

30x = 2400

x = 80

So, at 80 meals, the cost of the 2 venues will be the exact same

The length of a rectangle is twice the width if the perimeter of the rectangle 60 units find the area of the rectangle

Answers

Answer:

200

Step-by-step explanation:

Length = 2w

2w + 2l = 60

substitute l out with 2w

2w + 2(2w) = 60

2w + 4w = 60

w = 10

l = 20

Area = w • l

        = 10 • 20

        = 200

Mrs. Conley asks her class what kind of party they want to have to celebrate their excellent behavior. Out of all the students in the class, 5 want a ice cream party, 7 want a movie, 10 want a costume party, and the rest want are undecided. If 20% want a ice cream party, how many students are in class?

Answers

Answer:

25

Step-by-step explanation:

indicate in standard form the equation of the line passing through the given points, in the equation box below. X(0, 6), Y(5, 6)

Answers

Answer:

0x + y = 6

Step-by-step explanation:

Equation of the Line

The equation of a line passing through points (x1,y1) and (x2,y2) can be written as follows:

[tex]\displaystyle y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]

It can be later converted to any other form of the line. For example, the standard form is:

[tex]Ax + By = C[/tex]

Let's find the equation by using the given points (0,6) (5,6):

[tex]\displaystyle y-6=\frac{6-6}{5-0}(x-0)[/tex]

Operating:

[tex]\displaystyle y-6=\frac{0}{5-0}(x-0)[/tex]

y - 6 = 0

Or, equivalently:

0x + y = 6

This corresponds to a horizontal line

2. Graph x < 8 and x > -1.

Answers

Answer:

I'll try my best in explaining the steps.

Considering both signs are greater than and less than sign, its an open circle.

For the first equation, you would have an open circle, basically one that isn't colored in, on 8 on the number line. The arrow would be pointing to the left because the equation is telling us numbers that are less than 8.

For the second equation, you would have an open circle, basically one that isn't colored in, on -1 on the number line. The arrow would be pointing to the right because the equation is telling us numbers that are greater than -1.

Step-by-step explanation:

Please help I’ll mark brainliest if u give a small explanation

Answers

the answer is 4 because the bottom and line DE form a right angle

A taxi cab charges a flat fee of $1.75 plus $0.30 for each half-mile or fraction of a half-mile.

a) Fill in the chart.

b)write and equation for the function.

Answers

Answer:

a) there is no chart but we can elaborate one:

taxi fee            half-miles driven

$1.75                      0

$2.05                     1

$2.35                     2

$2.65                     3

$2.95                     4

$3.25                     5

$3.55                     6

b) y = 0.3x + 1.75

where:

y = taxi fee

x = half miles driven

Can someone please help, ty!!
(Will mark brainliest)

Answers

Answer:

Yellow is correct.

You can add the valued and divide by how many values there are to find the mean

The score of 20 is an outlier and brings the mean score down by almost 10%

Step-by-step explanation:

Answer:

3: The low score causes the mean to decrease.

Step-by-step explanation:

If you add a significantly lower number, it will bring down the overall average.

Hope this helps!

yler's brother earns $12 per hour. The store offers him a raise— a 5% increase per hour. after the raise,how much will tyler make per hour

Answers

Answer:

$12.60

Step-by-step explanation:

12/100 × 12 = 0.60

12 + 0.60 = 12.60

Write the slope-intercept form of the equation of the line described. through (2, -5) perpendicular to y = 1/3x -1

Answers

Answer:

y = -3x + 1

Step-by-step explanation:

Perpendicular lines have opposite reciprocal slopes, so the slope will be -3.

Plug in the slope and given point into y = mx + b

y = mx + b

-5 = -3(2) + b

-5 = -6 + b

1 = b

Then, plug in the slope and y intercept into y = mx + b again:

y = -3x + 1 will be the equation of the line

Martina ordered a set of blue and orange pins. She received 96 pins in all. 24 of the pins were
blue. What percentage of the pins were blue?
Write your answer using a percent sign (%).

Answers

Answer:

25%

Step-by-step explanation:

This is like a part over whole problem, where 24 blue pens is the part and 96 pens total is the whole.

24/96 = 0.25 * 100 = 25%

Answer:

Of the 96 pins, 25% of the pins were blue.

Step-by-step explanation:

We are given that Martina ordered 96 pins in total. We are also given that she ordered 24 blue pins.

With this, we can determine how many of the pins were not blue pins by subtracting the amount of blue pins from the number of total pins.

[tex]96 \ \text{total pins} - 24 \ \text{blue pins} = 72 \ \text{orange pins}[/tex]

Now, we can divide the number of blue pins by the number of total pins to determine the fraction of blue pins to total pins.

[tex]\displaystyle \frac{24}{96} = \frac{12}{48} = \frac{6}{24} = \frac{3}{12} = \frac{1}{4}[/tex]

Then, we can convert our fraction to a decimal.

[tex]\displaystyle \frac{1}{4} = 0.25[/tex]

And finally, we can convert our decimal to a percentage by multiplying the determined decimal by 100.

[tex]0.25\times100 = 25\%[/tex]

Therefore, of the 96 pins that Martina ordered, 25% of them were blue.

the is factoring quadratics with a leading coefficient: 5x to the 2 power - 14x + 8

Answers

Answer:

The factorization of [tex]5x^2-14x+8[/tex] is (5x-4)(x-2)

Step-by-step explanation:

Given quadratic polynomial is:

[tex]5x^2-14x+8[/tex]

To factor a quadratic polynomial with leading co-efficient has to be factorized, the leading co-efficient and the constant are multiplied and pairs(a,b) of the product are made so that their sum or subtraction is equal to the co-efficient of x

We get 40 by multiplying 8 and 5

And the pair we get are: 10 and 4

[tex]=5x^2-10x-4x+8\\=5x(x-2)-4(x-2)\\=(5x-4)(x-2)[/tex]

Hence,

The factorization of [tex]5x^2-14x+8[/tex] is (5x-4)(x-2)

2. What number is equal to five units + three tenths? Circle the correct answer.
0.53
0.35
5.3
3.5
53
35

Answers

Answer:

35

Step-by-step explanation:

5*1+3*10

5+30 = 35

Q14.
Solve the simultaneous equations
2x - 3y = 24
6x + 2y = -5
landimorament

Answers

-3y=24-2x
2y=-5-6x

-y=8-2/3x y=-8+2/3x
y=-5/2-3x

-8+2/3x=-5/2-3x
-8+5/2=-3x-2/3x
-11/2= -11/3x
x=3/2
hope it helps!!!

The diagram compares the ratio of girls in the chorus to boys in the chorus. What is the ratio of girls to boys? If there are 30 students in the chorus, how many are girls and how many are boys.

girls 3 parts
boys 2 parts

Answers

Answer:

it should be girls 12 to 18

Step-by-step explanation:

i just messed around with a calculator and found it.

(I'LL BE GIVING BRAINLIEST AND EXTRA POINTS TO WHO EVER HELPS ME!! :D)



Petra eats five and three fifths pies in a pie-eating contest. Paulie eats three and fourteen sixteenths pies in the contest. How many more pies did Petra eat?

A) one and fifty eight eightieths pies

B) one and seventeen twenty firsts pies

C) two and fifty eight eightieths pies

D) two and seventeen twenty firsts pies


(Here is an image if needed) :

Answers

Answer:

2 7/20

Step-by-step explanation:

find area of triangle formed by (1,1) (2,3) (4 ,5) using heron's formula ​

Answers

Answer:

The area of a triangle is:

A = 1 unit²

Step-by-step explanation:

Given the points of a triangle

A(1, 1)

B(2, 3)

C(4, 5)

[tex]\mathrm{Compute\:the\:distance\:between\:}\left(x_1,\:y_1\right),\:\left(x_2,\:y_2\right):\quad \sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}[/tex]

Distance between AB:

[tex]AB=\sqrt{\left(2-1\right)^2+\left(3-1\right)^2}[/tex]

     [tex]=\sqrt{1+4}[/tex]

     [tex]=\sqrt{5}[/tex]

so

[tex]a=\sqrt{5}[/tex]

Distance between BC:

[tex]BC=\sqrt{\left(4-2\right)^2+\left(5-3\right)^2}[/tex]

     [tex]=\sqrt{2^2+2^2}[/tex]

     [tex]=\sqrt{2^3}[/tex]

     [tex]=2\sqrt{2}[/tex]

so

[tex]b=2\sqrt{2}[/tex]

Distance between AC:

[tex]AC=\sqrt{\left(4-1\right)^2+\left(5-1\right)^2}[/tex]

    [tex]=\sqrt{3^2+4^2}[/tex]

   [tex]=\sqrt{5^2}[/tex]

    [tex]=5[/tex]

so

[tex]c=5[/tex]

Semiperimeter = sum of sides ÷ 2            

                       [tex]s=\frac{\sqrt{5}+2\sqrt{2}+5}{2}=5.03224[/tex]

Area of the triangle:

[tex]A=\sqrt{s\left(s-a\right)\left(s-b\right)\left(s-c\right)}[/tex]

[tex]a=\sqrt{5}[/tex][tex]b=2\sqrt{2}[/tex][tex]c=5[/tex]

[tex]A=\sqrt{s\left(s-\sqrt{5}\right)\left(s-2\sqrt{2}\right)\left(s-5\right)}[/tex]

[tex]A=\sqrt{5.03224\dots \left(5.03224\dots -\sqrt{5}\right)\left(5.03224\dots -2\sqrt{2}\right)\left(5.03224\dots -5\right)}[/tex]

[tex]A=1[/tex]

Therefore, the area of a triangle is:

A = 1 unit²

What is 8.15 rounded to the nearest whole number

Answers

Answer:

the answer is 8.

Step-by-step explanation:

Brainliest? uwu

Answer:

8 :)

You round down. If it was 8.5 then you'd round up, anything below would be rounded down, for example, 8.4, 8.3, 8.2, 8.1.

Evaluate the circulation of G =xyi +zj +4yk around a square of side 9, centered at the origin, lying in the yz-plane, and oriented counterclockwise when viewed from the positive x-axis.

Answers

Answer:

I didn't know the answer and sorry I am here taking freepoint because I needed them in a hurry so that I can ask my questions from someone else that's why I really sorry and thank you for free points

Find the values of a and b such that x² - 2x + 2 = ( x - a )² + b

Answers

Answer:

a = b = 1

Step-by-step explanation:

x² - 2x + 2 = ( x - a )² + b

x² - 2x + 2 = ( x² - 2x + 1) - 1 + 2 = (x - 1)² + 1

a = b = 1  

Helpppppppppppppp
asappppppppppp

Answers

Answer:

180-112=68

Step-by-step explanation:

State the number of complex roots and the possible number of real and imaginary roots for each equation. The find all roots? If possible.

Answers

Answer:

x =2

x = -2

Step-by-step explanation:

(x - 2)(x + 2)(x^2 + 4) = 0

(x - 2) = 0

x = 0 + 2

x =  2

(x + 2) = 0

x = - 2

x = - 2

(x^2 + 4) = 0

x^2 = 4

x = [tex]\sqrt{4}[/tex]

x = 2

5 yds=? Ft (PLEASE HELPP!!!)

Answers

Answer:

5 yards = 15 feet

Step-by-step explanation:

Following the formula that for every 1 yard we have 3 feet.

x = amount of yards

y = amount of feet per yard

z = amount of feet total

[tex]x * y = z[/tex]

Substitute:

[tex]5 * 3 = z[/tex]

[tex]15 =z[/tex]

Final answer:

5 yards = 15 feet

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